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 A204841 #10 Jan 10 2013 07:26:41
%S A204841 0,0,16,672,39936,3624960,478955520,87177646080,20922779566080,
%T A204841 6402373519933440,2432902004460748800,1124000727695858073600,
%U A204841 620448401731277448806400,403291461126554623829606400,304888344611712432172380979200,265252859812191015786434789376000
%N A204841 (2n)! - 2^n*n!.
%C A204841 a(n) is the number of ways to seat (linearly order) n married couples so that at least one couple is separated.
%F A204841 a(n) = A010050(n) - A000165(n).
%t A204841 Table[(2n)! - 2^n n!, {n,0,20}]
%Y A204841 Cf. A007060.
%K A204841 nonn
%O A204841 0,3
%A A204841 _Geoffrey Critzer_, Jan 19 2012