A377317 Numbers k such that prime(k), prime(k)+6, and prime(k)+12 are primes.

3, 4, 5, 7, 11, 13, 15, 18, 19, 25, 26, 36, 39, 49, 54, 55, 58, 69, 73, 102, 107, 110, 111, 116, 118, 129, 160, 164, 182, 184, 187, 194, 199, 206, 210, 218, 225, 229, 234, 236, 252, 253, 260, 271, 272, 275, 284, 285, 291, 300, 321, 339, 351, 352, 358, 387, 388

Offset

1,1

Links

Table of n, a(n) for n=1..57.

Formula

a(n) = pi(A023241(n)).

Example

5 is in this sequence because: prime(5) = 11, and 11+6 = 17 and 11+12 = 23 are primes.

Mathematica

Select[Range[1, PrimePi[3000]], PrimeQ[Prime[#] + 6] && PrimeQ[Prime[#] + 12] &]

Prog

(PARI) for(k=1, primepi(3000), p = prime(k); if(isprime(p+6) && isprime(p+12), print(k)))

Crossrefs

Cf. A000040, A000720, A023241.

Supersequence of A377318.

Sequence in context: A330109 A082378 A046642 * A330110 A330123 A354711

Adjacent sequences: A377313 A377314 A377315 * A377318 A377323 A377324

Keyword

nonn

Author

Kritsada Moomuang, Oct 24 2024

Status

approved