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 A277257 #15 Jul 04 2019 14:31:17 %S A277257 0,8,0,96,384,12,3456,460800,236160,96,168960,3065610240,125962905600, %T A277257 764467200,3120,12211200,51115799347200,453840358706380800, %U A277257 226918953109094400,6383697868800,115200,1196052480,1816224465420288000,6896429934345052028928000 %N A277257 Multi-table menage seating arrangements: T(n,k) for n,k >= 1 equals the number of ways to seat n*k married couples at n round tables with 2*k seats each, such that (i) the gender of persons alternates around each table; and (ii) spouses do not sit next to each other. %C A277257 Tables and seats are labeled. For unlabeled version, see A277265. %F A277257 T(n,k) = A277256(n,k) * 2^n * (n*k)!. %e A277257 Table T(n,k): %e A277257 n=1: 0, 0, 12, 96, 3120, 115200, ... %e A277257 n=2: 8, 384, 236160, 764467200, ... %e A277257 n=3: 96, 460800, 125962905600, ... %e A277257 n=4: 3456, 3065610240, 453840358706380800, ... %e A277257 ... %Y A277257 Cf. A059375 (row n=1), A277265. %K A277257 nonn,tabl %O A277257 1,2 %A A277257 _Max Alekseyev_, Oct 07 2016