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 A027147 #7 Oct 24 2019 16:05:11 %S A027147 1,12,56,480,2040,16576,69888,557568,2361600,18675712,79613952, %T A027147 626409472,2686867456,21071708160,90875494400,711081984000, %U A027147 3081088991232,24069137760256,104712901754880,816979824869376,3566715303624704,27800440481513472,121738713372819456,948129286114508800 %N A027147 a(n) = A027144(2n, n-2). %K A027147 nonn %O A027147 2,2 %A A027147 _Clark Kimberling_ %E A027147 More terms from _Sean A. Irvine_, Oct 24 2019