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Search: a006450 -id:a006450
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Primes p whose order of primeness A078442(p) is at least 8.
+10
12
5381, 52711, 648391, 2269733, 9737333, 17624813, 37139213, 50728129, 77557187, 131807699, 174440041, 259336153, 326851121, 368345293, 440817757, 563167303, 718064159, 751783477, 997525853, 1107276647, 1170710369, 1367161723
OFFSET
1,1
COMMENTS
Union of A058325-A058328, A093046 etc. - R. J. Mathar, Jul 07 2012
LINKS
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
FORMULA
a(n) = A049090(A049090(n)). - James G. Merickel, Feb 14 2010
a(n) = A000040(A057849(n)). - R. J. Mathar, Jul 07 2012
MATHEMATICA
Nest[ Prime, Range[35], 8] (* Robert G. Wilson v, Mar 15 2004 *)
PROG
(PARI) list(lim)=my(v=List(), q, r, s, t, u, vv, w); forprime(p=2, lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++) && isprime(u++) && isprime(vv++) && isprime(w++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 19 2017
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Nov 10 2000
EXTENSIONS
Name clarified by Andrew Howroyd, Nov 17 2024
STATUS
approved
Primes p whose order of primeness A078442(p) is at least 9.
+10
12
52711, 648391, 9737333, 37139213, 174440041, 326851121, 718064159, 997525853, 1559861749, 2724711961, 3657500101, 5545806481, 7069067389, 8012791231, 9672485827, 12501968177, 16123689073, 16917026909, 22742734291
OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 1381 terms from Robert G. Wilson v)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
MATHEMATICA
Nest[ Prime, Range[35], 9] (* Robert G. Wilson v, Mar 15 2004 *)
PROG
(PARI) list(lim)=my(v=List(), q, r, s, t, u, vv, w, x); forprime(p=2, lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++) && isprime(u++) && isprime(vv++) && isprime(w++) && isprime(x++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 19 2017
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Nov 10 2000
EXTENSIONS
Name clarified by Andrew Howroyd, Nov 17 2024
STATUS
approved
Primes p whose order of primeness A078442(p) is at least 11.
+10
12
9737333, 174440041, 3657500101, 16123689073, 88362852307, 175650481151, 414507281407, 592821132889, 963726515729, 1765037224331, 2428095424619, 3809491708961, 4952019383323, 5669795882633, 6947574946087, 9163611272327
OFFSET
1,1
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..47.
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
FORMULA
a(n) = prime(A057847(n)). - Andrew Howroyd, Nov 17 2024
MATHEMATICA
Nest[ Prime, Range[35], 11] (* Robert G. Wilson v, Mar 15 2004 *)
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Dec 12 2000
EXTENSIONS
Name clarified by Andrew Howroyd, Nov 17 2024
STATUS
approved
Primes p whose order of primeness A078442(p) is at least 12.
+10
12
174440041, 3657500101, 88362852307, 414507281407, 2428095424619, 4952019383323, 12055296811267, 17461204521323, 28871271685163, 53982894593057, 75063692618249, 119543903707171, 156740126985437, 180252380737439, 222334565193649
OFFSET
1,1
COMMENTS
Primes p whose primeness is > 12: 3657500101, 88362852307, 2428095424619, 12055296811267, 75063692618249, 156740126985437, ..., . - Robert G. Wilson v, Mar 15 2000
LINKS
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
FORMULA
a(n) = A058332(prime(n)). - Andrew Howroyd, Nov 17 2024
MATHEMATICA
Nest[ Prime, Range[35], 12] (* Robert G. Wilson v, Mar 15 2004 *)
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Mar 15 2000
EXTENSIONS
Name clarified by Andrew Howroyd, Nov 17 2024
STATUS
approved
Primes p(n) such that n is a second-order nonprime number.
+10
12
2, 19, 29, 43, 47, 53, 71, 79, 89, 97, 103, 113, 131, 137, 149, 151, 163, 167, 173, 193, 199, 223, 227, 229, 233, 251, 257, 263, 271, 293, 307, 311, 317, 337, 347, 349, 359, 379, 383, 389, 397, 409, 421, 439, 443, 449, 457, 463, 479, 487, 491, 503, 523, 541
OFFSET
1,1
COMMENTS
The prime/nonprime compound sequence ABB. - N. J. A. Sloane, Apr 06 2016
EXAMPLE
Nonprime(4) = 8.
The 8th prime is 19, the second entry.
MAPLE
For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016
MATHEMATICA
nonPrime[n_Integer] := FixedPoint[n + PrimePi[ # ] &, n]; Prime /@ nonPrime /@ nonPrime /@ Range[54] (* Robert G. Wilson v, Feb 04 2005 *)
PROG
(PARI) \We perform nesting(s) with a loop. cips(n, m) = { local(x, y, z); for(x=1, n, z=x; for(y=1, m+1, z=composite(z); ); print1(prime(z)", ") ) } composite(n) = \ The n-th composite number. 1 is defined as a composite number. { local(c, x); c=1; x=0; while(c <= n, x++; if(!isprime(x), c++); ); return(x) }
CROSSREFS
Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.
KEYWORD
nonn
AUTHOR
Cino Hilliard, Jan 31 2005
EXTENSIONS
Edited by Robert G. Wilson v, Feb 04 2005
STATUS
approved
The prime/nonprime compound sequence ABA.
+10
12
7, 13, 23, 37, 61, 73, 101, 107, 139, 181, 197, 239, 269, 281, 313, 373, 419, 433, 467, 499, 521, 577, 613, 653, 719, 751, 761, 811, 823, 853, 977, 1013, 1051, 1069, 1163, 1187, 1237, 1289, 1307, 1373, 1439, 1453, 1549, 1559, 1583
OFFSET
1,1
MAPLE
# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016
CROSSREFS
Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 30 2016
STATUS
approved
The prime/nonprime compound sequence BAA.
+10
12
6, 9, 18, 26, 45, 57, 81, 91, 112, 143, 165, 203, 228, 244, 267, 303, 345, 354, 411, 437, 454, 495, 530, 564, 623, 668, 687, 714, 728, 749, 856, 893, 931, 959, 1032, 1054, 1104, 1158, 1185, 1233, 1268, 1298, 1372, 1392, 1425, 1445, 1539, 1672, 1698, 1714, 1742, 1773, 1802, 1886, 1914, 1966, 2031, 2050, 2104
OFFSET
1,1
MAPLE
# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016
CROSSREFS
Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 30 2016
STATUS
approved
The prime/nonprime compound sequence BBA.
+10
12
8, 10, 15, 20, 27, 32, 38, 40, 49, 58, 63, 72, 78, 82, 88, 99, 110, 114, 121, 125, 129, 140, 146, 155, 166, 172, 175, 183, 185, 189, 212, 217, 225, 230, 245, 248, 258, 265, 272, 279, 289, 292, 306, 309, 315, 319, 334, 355, 360, 362, 368, 375, 377, 393, 402, 408, 416, 420, 427, 435, 438, 452, 473, 478, 482, 486, 507
OFFSET
1,1
MAPLE
# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016
CROSSREFS
Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 30 2016
STATUS
approved
MM-numbers of labeled graphs with loops, without isolated vertices.
+10
12
1, 7, 13, 23, 29, 43, 47, 73, 79, 91, 97, 101, 137, 139, 149, 161, 163, 167, 199, 203, 227, 233, 257, 269, 271, 293, 299, 301, 313, 329, 347, 373, 377, 389, 421, 439, 443, 449, 467, 487, 491, 499, 511, 553, 559, 577, 607, 611, 631, 647, 653, 661, 667, 673, 677
OFFSET
1,2
COMMENTS
Here a loop is an edge with two equal vertices, distinguished from a half-loop, which has only one vertex.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. The multiset of multisets with MM-number n is formed by taking the multiset of prime indices of each part of the multiset of prime indices of n. For example, the prime indices of 78 are {1,2,6}, so the multiset of multisets with MM-number 78 is {{},{1},{1,2}}.
Also products of distinct primes whose prime indices are semiprimes, where a semiprime (A001358) is a product of any two prime numbers.
EXAMPLE
The sequence of terms together with their corresponding multisets of multisets (edge sets) begins:
1: {} 161: {{1,1},{2,2}} 347: {{2,9}}
7: {{1,1}} 163: {{1,8}} 373: {{1,12}}
13: {{1,2}} 167: {{2,6}} 377: {{1,2},{1,3}}
23: {{2,2}} 199: {{1,9}} 389: {{4,5}}
29: {{1,3}} 203: {{1,1},{1,3}} 421: {{1,13}}
43: {{1,4}} 227: {{4,4}} 439: {{3,7}}
47: {{2,3}} 233: {{2,7}} 443: {{1,14}}
73: {{2,4}} 257: {{3,5}} 449: {{2,10}}
79: {{1,5}} 269: {{2,8}} 467: {{4,6}}
91: {{1,1},{1,2}} 271: {{1,10}} 487: {{2,11}}
97: {{3,3}} 293: {{1,11}} 491: {{1,15}}
101: {{1,6}} 299: {{1,2},{2,2}} 499: {{3,8}}
137: {{2,5}} 301: {{1,1},{1,4}} 511: {{1,1},{2,4}}
139: {{1,7}} 313: {{3,6}} 553: {{1,1},{1,5}}
149: {{3,4}} 329: {{1,1},{2,3}} 559: {{1,2},{1,4}}
MATHEMATICA
Select[Range[100], SquareFreeQ[#]&&FreeQ[If[#==1, {}, FactorInteger[#]], {p_, k_}/; PrimeOmega[PrimePi[p]]!=2]&]
CROSSREFS
The case with only one edge is A106349.
The case covering an initial interval is A320461.
The version allowing multiple edges is A339112.
The half-loop version covering an initial interval is A340018.
The half-loop version is A340019.
A006450 lists primes of prime index.
A302242 is the weight of the multiset of multisets with MM-number n.
A302494 lists MM-numbers of sets of sets, with connected case A328514.
A309356 lists MM-numbers of simple graphs.
A339113 lists MM-numbers of multigraphs.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jan 02 2021
STATUS
approved
Composite numbers whose prime indices are also composite.
+10
11
49, 91, 133, 161, 169, 203, 247, 259, 299, 301, 329, 343, 361, 371, 377, 427, 437, 481, 497, 511, 529, 551, 553, 559, 611, 623, 637, 667, 679, 689, 703, 707, 721, 749, 791, 793, 817, 841, 851, 893, 917, 923, 931, 949, 959, 973, 989, 1007, 1027, 1043, 1057
OFFSET
1,1
COMMENTS
A prime index of n is a number m such that prime(m) divides n.
EXAMPLE
The sequence of terms begins:
49 = prime(4)^2
91 = prime(4)*prime(6)
133 = prime(4)*prime(8)
161 = prime(4)*prime(9)
169 = prime(6)^2
203 = prime(4)*prime(10)
247 = prime(6)*prime(8)
259 = prime(4)*prime(12)
299 = prime(6)*prime(9)
301 = prime(4)*prime(14)
329 = prime(4)*prime(15)
343 = prime(4)^3
361 = prime(8)^2
371 = prime(4)*prime(16)
377 = prime(6)*prime(10)
427 = prime(4)*prime(18)
437 = prime(8)*prime(9)
481 = prime(6)*prime(12)
497 = prime(4)*prime(20)
511 = prime(4)*prime(21)
529 = prime(9)^2
551 = prime(8)*prime(10)
553 = prime(4)*prime(22)
559 = prime(6)*prime(14)
611 = prime(6)*prime(15)
623 = prime(4)*prime(24)
637 = prime(4)^2*prime(6)
MATHEMATICA
Select[Range[2, 1000], And[OddQ[#], !PrimeQ[#], And@@Not/@PrimeQ/@PrimePi/@First/@FactorInteger[#]]&]
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 18 2018
STATUS
approved

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