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 A258261 #30 Sep 08 2022 08:46:12 %S A258261 2,3,5,7,11,17,19,29,31,37,47,59,61,67,79,89,107,131,149,151,157,191, %T A258261 197,199,227,229,241,271,277,281,311,317,367,389,397,409,421,431,457, %U A258261 479,499,509,521,541,547,557,571,617,631,659,661,677,691,701,719 %N A258261 Primes p such that 3p - 4 is also prime. %C A258261 This sequence is interesting because of the comments in A258233: for n > 1, if 3 * prime(n) - 4 is prime then A258233(n) = 1 + A071704(n), otherwise A258233 (n) = A071704(n). - _Zak Seidov_, Jun 04 2015 %C A258261 Subsequence of primes of A228121. - _Michel Marcus_, May 30 2015 %e A258261 3 * 2 - 4 = 2, 3 * 3 - 4 = 5, 3 * 5 - 4 = 11, 3 * 7 - 4 = 17, 3 * 11 - 4 = 29 are all prime, so 2, 3, 5, 7, 11 are all in the sequence. %e A258261 3 * 13 - 4 = 35 = 5 * 7, so 13 is not in the sequence. %t A258261 Select[Prime[Range[200]], PrimeQ[3# - 4] &] %o A258261 (Magma) [p: p in PrimesUpTo(1000) | IsPrime(3*p-4)]; // _Vincenzo Librandi_, May 25 2015 %o A258261 (PARI) forprime(p=1,10^3,if(isprime(3*p-4),print1(p,", "))) \\ _Derek Orr_, May 27 2015 %Y A258261 Cf. A023209 (3p + 4), A071704, A258233, A228353, A228121. %K A258261 nonn,easy %O A258261 1,1 %A A258261 _Zak Seidov_, May 24 2015