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 A027241 #8 Oct 26 2019 15:27:30
%S A027241 1,7,38,201,991,5119,25108,131207,652171,3467959,17536482,94772169,
%T A027241 487259131,2668269045,13920305080,77008669339,406737748473,
%U A027241 2267418205201,12099265896022,67836037484417,365071772684071,2055622507395167,11141223793940397,62938095325080771
%N A027241 a(n) = Sum_{k=0..n-2} T(n,k) * T(n,k+2), with T given by A026769.
%K A027241 nonn
%O A027241 2,2
%A A027241 _Clark Kimberling_
%E A027241 More terms from _Sean A. Irvine_, Oct 26 2019