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 A027227 #9 Oct 25 2019 04:58:29
%S A027227 1,3,10,25,71,166,444,1002,2601,5742,14653,31864,80472,173077,434243,
%T A027227 926144,2313939,4902478,12216163,25743143,64042535,134356858,
%U A027227 333927795,697932219,1733779702,3612110059,8971527052,18639230426
%N A027227 a(n) = Sum_{k=0..n} (k+1) * A026747(n, k).
%K A027227 nonn
%O A027227 0,2
%A A027227 _Clark Kimberling_