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 A020245 #14 Apr 25 2016 11:45:28
%S A020245 9,49,169,343,1849,2353,2701,4033,4681,6541,6697,7957,9997,12403,
%T A020245 13213,13747,15251,16531,18769,19729,24761,30589,31621,31861,32477,
%U A020245 41003,49771,63139,64681,65161,66421,68257,73555,96049,102831,118957,129961,137311
%N A020245 Strong pseudoprimes to base 19.
%H A020245 R. J. Mathar, <a href="/A020245/b020245.txt">Table of n, a(n) for n = 1..752</a>
%H A020245 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%o A020245 (PARI) /* with A001262 */
%o A020245 isA020245(n)={ isStrongPsp(n,19) }
%o A020245 { for(n=1,300000000, if(isA020245(n), print(n) ;) ;) ;} /* R. J. Mathar, Mar 07 2012 */
%K A020245 nonn
%O A020245 1,1
%A A020245 _David W. Wilson_