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 A027287 #5 Mar 30 2012 18:56:15 %S A027287 1,2,6,15,54,118,471,973,4128,8262,36481,71534,324876,627926,2911923, %T A027287 5568348,26241376,49767432,237550401,447567059,2158650078,4045351674, %U A027287 19679880649,36716551814,179920446576,334415846660 %N A027287 Self-convolution of array T given by A026009. %K A027287 nonn %O A027287 0,2 %A A027287 _Clark Kimberling_