|
%I #5 Dec 18 2015 18:17:25
%S 0,0,0,0,0,1350,529200,172872000,58352555520,21677788944000,
%T 9059008787136000,4286753834515891200,2297335836334687948800,
%U 1390520517156693315993600,946759961227258909995264000
%N Number of n X n (0,1) matrices with two 1's in each row and permanent equal to 8.
%C If a (0,1) matrix with two 1's in each row has positive permanent, then it equals to a power of 2.
%D J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1967, Ch.4, 66-79.
%D V. S. Shevelev, On the permanent of the stochastic (0,1)-matrices with equal row sums, Izvestia Vuzov of the North-Caucasus region, Nature sciences 1 (1997), 21-38 (in Russian)
%F In general, for m>=1: number of n X n (0,1) matrices with two 1's in each row the permanent of which equals 2^m is n!*n^(n-1)*2^(-m)*Sum{k=2,...,n}kn^(-k)*C(n,k)*d(k,m), where d(k,m) are associated Stirling numbers of the first kind (see Riordan, p. 75).
%Y Cf. A174586 A001866 A174637
%K nonn
%O 1,6
%A _Vladimir Shevelev_, Mar 25 2010
|
