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 A248221 #19 Oct 06 2014 16:27:42
%S A248221 1,3,6,10,13,18,21,24,25,31,36,39,40,43,45,46,49,55,60,64,66,73,78,85,
%T A248221 91,94,96,109,115,123,124,126,129,130,133,138,139,141,144,145,151,154,
%U A248221 159,165,168,171,174,178,181,189,193,195,196,201,211,223,225,229
%N A248221 Numbers m such that 52*m + 1 is prime.
%C A248221 All terms are == {0,1} mod 3, because 52*(3k+2) + 1 is divisible by 3. - _Zak Seidov_, Oct 05 2014
%H A248221 Zak Seidov, <a href="/A248221/b248221.txt">Table of n, a(n) for n = 1..2000</a>
%F A248221 a(n) = (A142508(n) - 1)/52.
%p A248221 A248221:=n->`if`(isprime(52*n+1), n, NULL): seq(A248221(n), n=1..500); # _Wesley Ivan Hurt_, Oct 05 2014
%t A248221 Select[Range[250], PrimeQ[52# + 1] &] (* _Alonso del Arte_, Oct 04 2014 *)
%o A248221 (PARI)
%o A248221 for(n=1,10^3,if(isprime(52*n+1),print1(n,", "))) \\ _Derek Orr_, Oct 05 2014
%Y A248221 Cf. A033210, A142508.
%K A248221 nonn,easy
%O A248221 1,2
%A A248221 _Zak Seidov_, Oct 04 2014
%E A248221 More terms from _Wesley Ivan Hurt_, Oct 05 2014