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 A027455 #5 Mar 30 2012 17:20:43 %S A027455 15,65,175,9963,5368,1105000,5720625,105686875,75492928,74269960128, %T A027455 56445795000,96454009575000,76498373160000,61692439558464, %U A027455 403805999193597,1643804692663258125,1377243480733120000 %N A027455 Second diagonal of A027448. %F A027455 Numerators of sequence a[ n, n-1 ] in (a[ i, j ])^4 where a[ i, j ] = 1/i if j<=i, 0 if j>i %K A027455 nonn %O A027455 2,1 %A A027455 _Olivier Gérard_