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 A151588 #3 Mar 31 2012 12:35:18 %S A151588 0,760,911520,222334560,25996425216,1996732745784,117482611237280 %N A151588 Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly 7 adjacent element pairs in decreasing order. %K A151588 nonn %O A151588 4,2 %A A151588 _R. H. Hardin_ May 21 2009