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 A303740 #18 May 05 2025 03:00:54
%S A303740 13,43,157,241,463,601,757,1123,2971,3307,4423,4831,5701,6163,8191,
%T A303740 9901,11131,12433,13807,19183,20023,21757,22651,23563,26407,28393,
%U A303740 35911,37057,53593,60763,78121,83233,95791,113233,117307,121453,123553,127807,136531,143263
%N A303740 Primes of the form 9*k^2 + 3*k + 1.
%H A303740 Robert Israel, <a href="/A303740/b303740.txt">Table of n, a(n) for n = 1..10000</a>
%F A303740 a(n) = A082040(A303739(n)). - _Elmo R. Oliveira_, May 04 2025
%p A303740 select(isprime,[seq(9*n^2+3*n+1,n=0..500)]);
%t A303740 Select[Table[9 n^2 + 3 n + 1, {n, 0, 150}], PrimeQ] (* _Vincenzo Librandi_, Jun 25 2018 *)
%o A303740 (GAP) Filtered(List([0..300],n->9*n^2+3*n+1),IsPrime);
%o A303740 (Magma) [a: n in [0..200] | IsPrime(a) where a is 9*n^2 +3*n+1 ];// _Vincenzo Librandi_, Jun 25 2018
%Y A303740 Cf. A303739.
%Y A303740 Subsequence of A082040.
%K A303740 nonn,easy
%O A303740 1,1
%A A303740 _Muniru A Asiru_, Jun 01 2018