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 A027259 #8 Oct 26 2019 15:57:41
%S A027259 5,40,342,2941,25333,218659,1891683,16403283,142548639,1241293314,
%T A027259 10829045472,94632148659,828235716571,7258991679448,63701900660206,
%U A027259 559673483274827,4922447330226279,43336501329817600,381873520840930490,3367815295820010367,29724409053210972087
%N A027259 a(n) = Sum_{k=0..2n-2} T(n,k) * T(n,k+2), with T given by A025177.
%K A027259 nonn
%O A027259 2,1
%A A027259 _Clark Kimberling_
%E A027259 More terms from _Sean A. Irvine_, Oct 26 2019