A059325 -id:A059325 - cp's OEIS frontend

A023221 Primes p such that 6*p + 5 is also prime.

2, 3, 7, 11, 13, 17, 29, 31, 37, 41, 43, 59, 71, 73, 79, 83, 97, 107, 109, 113, 137, 139, 151, 157, 163, 181, 191, 193, 197, 227, 239, 241, 251, 263, 269, 277, 307, 311, 317, 337, 347, 349, 367, 373, 389, 401, 409, 421, 431, 443, 449, 479, 487, 499, 503, 541, 557, 577, 587

Offset: 1

David W. Wilson

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Subsequence of A059325.

[n: n in PrimesUpTo(100) | IsPrime(6*n+5)]; // Vincenzo Librandi, Nov 20 2010

Select[Prime[Range[1000]], PrimeQ[6 # + 5] &] (* Vincenzo Librandi, May 20 2014 *)

A056956 Numbers n such that 6n+1 and 6n+5 are both primes.

Original entry on oeis.org

1, 2, 3, 6, 7, 11, 13, 16, 17, 18, 21, 27, 32, 37, 38, 46, 51, 52, 58, 63, 66, 73, 76, 77, 81, 83, 102, 107, 112, 123, 126, 128, 137, 142, 143, 146, 147, 151, 156, 161, 168, 181, 182, 202, 213, 216, 217, 237, 238, 241, 247, 248, 258, 261, 263, 266, 268, 277, 282

Offset: 1

Henry Bottomley, Jul 18 2000

nonn

Note that if prime p>3 then p mod 6 = 1 or 5.

			a(2)=2 since 6*2+1=13 and 6*2+5=17 are both prime.

M. F. Hasler, Table of n, a(n) for n = 1..5000

Cf. A002822, A024898, A024899, A059325.

Select[Range[300], And @@ PrimeQ /@ ({1, 5} + 6#) &] (* Ray Chandler, Jun 29 2008 *)

is(n)=isprime(n*6+1)&&isprime(n*6+5) \\ M. F. Hasler, Apr 05 2017

a(n) = (A023200(n+1)-1)/6 = (A046132(n+1)-5)/6 = A047847(n+1)/3

a(n) = floor(A087679(n+1)/6). - M. F. Hasler, Apr 05 2017

Edited by N. J. A. Sloane, Nov 07 2006

A059324 Numbers n such that 6n + 5 is composite.

Original entry on oeis.org

5, 10, 12, 15, 19, 20, 23, 25, 26, 30, 33, 34, 35, 36, 40, 45, 47, 49, 50, 53, 54, 55, 56, 60, 61, 62, 65, 67, 68, 70, 72, 75, 78, 80, 82, 85, 87, 88, 89, 90, 91, 95, 96, 100, 101, 103, 104, 105, 110, 111, 114, 115, 117, 118, 120, 121, 122, 124, 125, 127, 129, 130

Offset: 1

Anton Joha, Jan 26 2001

Conjecture: There exists no pair of primes (p, q > p^2) such that q - p^2 = 6*n - 4 (see A138479). - Philippe LALLOUET (philip.lallouet(AT)orange.fr), Mar 20 2008

			a(3) = 12 because 6*12 + 5 = 77 is composite.

G. C. Greubel, Table of n, a(n) for n = 1..5000

Complement of A059325.

Cf. A138479.

Select[Range[200],!PrimeQ[6#+5]&]  (* Harvey P. Dale, Mar 13 2011 *)

isok(n) = ! isprime(6*n+5); \\ Michel Marcus, Jan 06 2017

a(n) = A046953(n-1) - 1.

More terms from Henry Bottomley, Jan 29 2001

A023288 Primes that remain prime through 3 iterations of function f(x) = 6x + 5.

Original entry on oeis.org

2, 11, 13, 31, 71, 83, 151, 163, 193, 197, 317, 347, 373, 503, 577, 811, 911, 919, 1049, 1051, 1201, 1423, 1721, 1907, 2089, 2243, 2543, 2719, 2963, 3529, 3583, 3607, 3797, 4091, 4153, 4217, 4243, 4409, 4591, 4637, 4783, 5209, 5557, 5783, 5849, 5923, 6091

Offset: 1

David W. Wilson

nonn

Primes p such that 6*p+5, 36*p+35 and 216*p+215 are also primes. - Vincenzo Librandi, Aug 04 2010

John Cerkan, Table of n, a(n) for n = 1..10000

Subsequence of A023221, A023257, and A059325.

[n: n in [1..150000] | IsPrime(n) and IsPrime(6*n+5) and IsPrime(36*n+35) and IsPrime(216*n+215)] // Vincenzo Librandi, Aug 04 2010

A307561 Numbers k such that both 6k - 1 and 6k + 5 are prime.

Original entry on oeis.org

1, 2, 3, 4, 7, 8, 9, 14, 17, 18, 22, 28, 29, 32, 38, 39, 42, 43, 44, 52, 58, 59, 64, 74, 77, 84, 93, 94, 98, 99, 107, 108, 109, 113, 137, 143, 147, 157, 158, 162, 163, 169, 182, 183, 184, 197, 198, 203, 204, 213, 214, 217, 227, 228, 238, 239, 247, 248, 249, 259, 267, 268, 269, 312, 317, 318, 329, 333, 344

Offset: 1

Sally Myers Moite, Apr 14 2019

nonn

There are 146 terms below 10^3, 831 terms below 10^4, 5345 terms below 10^5, 37788 terms below 10^6 and 280140 terms below 10^7.
Prime pairs differing by 6 are called "sexy" primes. Other prime pairs with difference 6 are of the form 6n + 1 and 6n + 7.
Numbers in this sequence are those which are not 6cd + c - d - 1, 6cd + c - d, 6cd - c + d - 1 or 6cd - c + d, that is, they are not (6c - 1)d + c - 1, (6c - 1)d + c, (6c + 1)d - c - 1 or (6c + 1)d - c.

			a(2) = 2, so 6(2) - 1 = 11 and 6(2) + 5 = 17 are both prime.

Amiram Eldar, Table of n, a(n) for n = 1..10000
Sally M. Moite, "Primeless" Sieves for Primes and for Prime Pairs Which Differ by 2m, vixra:1903.0353 (2019).

Primes differing from each other by 6 are A023201, A046117.
Similar sequences for twin primes are A002822, A067611, for "cousin" primes A056956, A186243.
Intersection of A024898 and A059325.
Cf. also A307562, A307563.

Select[Range[500], PrimeQ[6# - 1] && PrimeQ[6# + 5] &] (* Alonso del Arte, Apr 14 2019 *)

is(k) = isprime(6*k-1) && isprime(6*k+5); \\ Jinyuan Wang, Apr 20 2019

A023317 Primes that remain prime through 4 iterations of function f(x) = 6x + 5.

Original entry on oeis.org

11, 13, 83, 151, 317, 373, 1721, 3529, 4153, 4243, 4637, 4783, 5209, 5849, 5923, 6661, 8431, 10903, 11329, 14519, 16183, 16979, 20149, 26669, 27509, 27827, 29873, 29947, 32987, 33637, 33937, 34919, 35099, 35543, 36277, 36691, 38069, 38461, 41651, 47407

Offset: 1

David W. Wilson

nonn

Primes p such that 6*p+5, 36*p+35, 216*p+215 and 1296*p+1295 are also primes. - Vincenzo Librandi, Aug 04 2010

John Cerkan, Table of n, a(n) for n = 1..10000

Subsequence of A023221, A023257, A023288, and A059325.

[n: n in [1..1000000] | IsPrime(n) and IsPrime(6*n+5) and IsPrime(36*n+35) and IsPrime(216*n+215) and IsPrime(1296*n+1295)] // Vincenzo Librandi, Aug 04 2010

if4Q[n_]:=AllTrue[Rest[NestList[6#+5&,n,4]],PrimeQ]; Select[Prime[ Range[ 5000]],if4Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 10 2018 *)

A173178 Numbers k such that 2k+3 is a prime of the form 3A024893(m) + 2.

Original entry on oeis.org

1, 4, 7, 10, 13, 19, 22, 25, 28, 34, 40, 43, 49, 52, 55, 64, 67, 73, 82, 85, 88, 94, 97, 112, 115, 118, 124, 127, 130, 133, 139, 145, 154, 157, 172, 175, 178, 190, 193, 199, 208, 214, 220, 223, 229, 232, 238, 244, 250, 253, 259, 277, 280, 283, 292, 295, 298, 307, 319

Offset: 1

Eric Desbiaux, Feb 11 2010

With the Bachet-Bézout theorem implicating Gauss Lemma and the Fundamental Theorem of Arithmetic,
for k > 1, k = 2*a + 3*b (a and b integers)
first type
A001477 = (2*A080425) + (3*A008611)
A000040 = (2*A039701) + (3*A157966)
A024893 Numbers k such that 3*k + 2 is prime
A034936 Numbers k such that 3*k + 4 is prime
OR second type
A001477 = (2*A028242) + (3*A059841)
A000040 = (2*A067076) + (3*1)
A067076 Numbers k such that 2*k + 3 is prime
   k   a b OR a b
  --   - -    - -
   0   0 0    0 0
   1   - -    - -
   2   1 0    1 0
   3   0 1    0 1
   4   2 0    2 0
   5   1 1    1 1
   6   0 2    3 0
   7   2 1    2 1
   8   1 2    4 0
   9   0 3    3 1
  10   2 2    5 0
  11   1 3    4 1
  12   0 4    6 0
  13   2 3    5 1
  14   1 4    7 0
  15   0 5    6 1
  ...
  2* 1 + 3 OR 3* 1 + 2 =  5;
  2* 4 + 3 OR 3* 3 + 2 = 11;
  2* 7 + 3 OR 3* 5 + 2 = 17;
  2*10 + 3 OR 3* 7 + 2 = 23;
  2*13 + 3 OR 3* 9 + 2 = 29;
  2*19 + 3 OR 3*13 + 2 = 41;
  2*22 + 3 OR 3*15 + 2 = 47;
  2*25 + 3 OR 3*17 + 2 = 53;
  2*28 + 3 OR 3*19 + 2 = 59.
A024893 Numbers k such that 3k+2 is prime.
A007528 Primes of the form 6k-1.
A024898 Positive integers k such that 6k-1 is prime.
1, 4, 7, 10, 13, 19, ... = (3*(4*A024898 - A024893) - 7)/2 = (A112774 - 3*A024893 - 5)/2 = A003627 - (3*A024893 - 5)/2.

Amiram Eldar, Table of n, a(n) for n = 1..10000
Chris K. Caldwell, FAQ: Are all primes (past 2 and 3) of the forms 6n+1 and 6n-1?, Frequently asked questions about primes.

Cf. A067076, A024893, A007528, A024898, A059325.

Select[Range[0, 320], PrimeQ[(p = 2*# + 3)] && Mod[p, 3] == 2 &] (* Amiram Eldar, Jul 30 2024 *)

a(n) = 3*A059325(n) + 1. - Amiram Eldar, Jul 30 2024

Data corrected and extended by Amiram Eldar, Jul 30 2024

A023345 Primes that remain prime through 5 iterations of function f(x) = 6x + 5.

Original entry on oeis.org

13, 4637, 5849, 5923, 16183, 16979, 34919, 36277, 67003, 79337, 115571, 159739, 175141, 245753, 249133, 305717, 341569, 359353, 383833, 437263, 455317, 498497, 511519, 567121, 579961, 581699, 633797, 683831, 693431, 849197, 972197, 1022449

Offset: 1

David W. Wilson

nonn

Primes p such that 6*p+5, 36*p+35, 216*p+215, 1296*p+1295 and 7776*p+7775 are also primes. - Vincenzo Librandi, Aug 05 2010

John Cerkan, Table of n, a(n) for n = 1..10000

Subsequence of A023221, A023257, A023288, A023317, and A059325.

[n: n in [1..10000000] | IsPrime(n) and IsPrime(6*n+5) and IsPrime(36*n+35) and IsPrime(216*n+215) and IsPrime(1296*n+1295) and IsPrime(7776*n+7775)] // Vincenzo Librandi, Aug 05 2010

Select[Range[1100000],And@@PrimeQ[NestList[6#+5&,#,5]]&] (* Harvey P. Dale, Mar 31 2012 *)

cp's OEIS Frontend

A023221 Primes p such that 6*p + 5 is also prime.

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A056956 Numbers n such that 6n+1 and 6n+5 are both primes.

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A059324 Numbers n such that 6n + 5 is composite.

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A023288 Primes that remain prime through 3 iterations of function f(x) = 6x + 5.

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Magma

A307561 Numbers k such that both 6*k - 1 and 6*k + 5 are prime.

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PARI

A023317 Primes that remain prime through 4 iterations of function f(x) = 6x + 5.

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Magma

Mathematica

A173178 Numbers k such that 2*k+3 is a prime of the form 3*A024893(m) + 2.

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A023345 Primes that remain prime through 5 iterations of function f(x) = 6x + 5.

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A307561 Numbers k such that both 6k - 1 and 6k + 5 are prime.

A173178 Numbers k such that 2k+3 is a prime of the form 3A024893(m) + 2.