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 A259785 #7 Dec 31 2015 07:09:47 %S A259785 1,1,3,44,1285,59963,4113244,389384029,48627012403,7743988554848, %T A259785 1531612782695209,368303149768896363,105818590347793426632 %N A259785 Number of permutations p of [2n] with no fixed points where the maximal displacement of an element equals n. %F A259785 a(n) = A259784(2n,n). %e A259785 a(0) = 1: (the empty permutation). %e A259785 a(1) = 1: 21. %e A259785 a(2) = 3: 2413, 3142, 3412. %e A259785 a(3) = 44: 214563, 215643, 216345, ..., 451623, 452163, 456123. %Y A259785 Cf. A259784. %K A259785 nonn,more %O A259785 0,3 %A A259785 _Alois P. Heinz_, Jul 05 2015