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 A238920 #4 Mar 08 2014 03:32:37 %S A238920 0,0,0,0,0,0,0,0,0,0,764,5008,23980,98846,375950,1353992,4719178, %T A238920 16089515,54175927,182019983,614507621,2078949960,7035318948, %U A238920 23778288812,80187314884,269618757792,903570999504,3017802963584,10047020559840,33357290774560 %N A238920 Number of self-inverse permutations p on [n] where the maximal displacement of an element equals 9. %H A238920 Joerg Arndt and Alois P. Heinz, <a href="/A238920/b238920.txt">Table of n, a(n) for n = 0..750</a> %Y A238920 Column k=9 of A238889. %K A238920 nonn %O A238920 0,11 %A A238920 _Joerg Arndt_ and _Alois P. Heinz_, Mar 07 2014