This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A377317 #15 Nov 10 2024 22:43:26 %S A377317 3,4,5,7,11,13,15,18,19,25,26,36,39,49,54,55,58,69,73,102,107,110,111, %T A377317 116,118,129,160,164,182,184,187,194,199,206,210,218,225,229,234,236, %U A377317 252,253,260,271,272,275,284,285,291,300,321,339,351,352,358,387,388 %N A377317 Numbers k such that prime(k), prime(k)+6, and prime(k)+12 are primes. %F A377317 a(n) = pi(A023241(n)). %e A377317 5 is in this sequence because: prime(5) = 11, and 11+6 = 17 and 11+12 = 23 are primes. %t A377317 Select[Range[1, PrimePi[3000]], PrimeQ[Prime[#] + 6] && PrimeQ[Prime[#] + 12] &] %o A377317 (PARI) for(k=1, primepi(3000), p = prime(k); if(isprime(p+6) && isprime(p+12), print(k))) %Y A377317 Cf. A000040, A000720, A023241. %Y A377317 Supersequence of A377318. %K A377317 nonn %O A377317 1,1 %A A377317 _Kritsada Moomuang_, Oct 24 2024