A277256 Multi-table menage numbers T(n,k) for n,k >= 1 equals the number of ways to seat the gentlemen from 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; provided that the ladies are already properly seated (i.e., no two ladies sit next to each other).
0, 1, 0, 2, 4, 1, 9, 80, 82, 2, 44, 4752, 43390, 4740, 13, 265, 440192, 59216968, 59216648, 439794, 80, 1854, 59245120, 164806652728, 2649391488016, 164806435822, 59216644, 579, 14833, 10930514688, 817056761525488, 312400218967336992, 312400218673012936, 817056406224656, 10927434466, 4738
Offset: 1
Examples
Table T(n,k): n=1: 0, 0, 1, 2, ... n=2: 1, 4, 82, 4740, ... n=3: 2, 80, 43390, 59216648, ... n=4: 9, 4752, 59216968, 2649391488016, ... n=5: 44, 440192, 164806652728, 312400218967336992, ... ...
Crossrefs
Programs
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PARI
{ A277256(n,k) = my(m,s,g); m=n*k; s=sqrt(1+4*x+O(x^(m+1))); g=if(k==1,1+z,((1-s)/2)^(2*k)+((1+s)/2)^(2*k))^n; sum(j=0,m,(-1)^j*polcoeff(g,j)*(m-j)!); }
Formula
T(n,k) = Sum_{j=0..n*k} (-1)^j * (n*k-j)! * [z^j] F(k,z)^n, where F(1,z) = 1+z and F(k,z) = ((1-sqrt(1+4*z))/2)^(2*k) + ((1+sqrt(1+4*z))/2)^(2*k) for k >= 2. [Corrected by Pontus von Brömssen, Jun 01 2022]
T(n,k) = A341439(n,n*k). - Pontus von Brömssen, May 31 2022
Comments