A303740 - OEIS

%I #12 Sep 08 2022 08:46:21

%S 13,43,157,241,463,601,757,1123,2971,3307,4423,4831,5701,6163,8191,

%T 9901,11131,12433,13807,19183,20023,21757,22651,23563,26407,28393,

%U 35911,37057,53593,60763,78121,83233,95791,113233,117307,121453,123553,127807,136531

%N Primes of the form 9*k^2 + 3*k + 1 (A082040).

%H Robert Israel, <a href="/A303740/b303740.txt">Table of n, a(n) for n = 1..10000</a>

%p select(isprime,[seq(9*n^2+3*n+1,n=0..500)]);

%t Select[Table[9 n^2 + 3 n + 1, {n, 0, 150}], PrimeQ] (* _Vincenzo Librandi_, Jun 25 2018 *)

%o (GAP) Filtered(List([0..300],n->9*n^2+3*n+1),IsPrime);

%o (Magma) [a: n in [0..200] | IsPrime(a) where a is 9*n^2 +3*n+1 ];// _Vincenzo Librandi_, Jun 25 2018

%Y Cf. A303739. Subsequence of A082040.

%K nonn,easy

%O 1,1

%A _Muniru A Asiru_, Jun 01 2018