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 A144339 #5 Jul 03 2023 14:52:19 %S A144339 1,4,52,648,12888,286272,8182944,266366016,10191545280,437925035520, %T A144339 21158411936256,1127285473434624,65884689657464832, %U A144339 4181915450891501568,286704379021188538368,21099339893878107144192,1659252422924430692327424,138827012602215571388891136 %N A144339 Second column (m=2) of triangle S2hat(-4) = A144285. %F A144339 a(n) = A144285(n+2,2), n>=0. %Y A144339 Cf. A144285, A008546 (m=1 column), A144340 (m=3 column). %K A144339 nonn,easy %O A144339 0,2 %A A144339 _Wolfdieter Lang_, Oct 09 2008