

A285179


Number of disjoint nonordered pairs of n^2 X n^2 Spermutation matrices.


2




OFFSET

1,2


COMMENTS

Note that although the two Yordzhev papers have similar titles, they are different papers.


LINKS

Table of n, a(n) for n=1..6.
Krasimir Yordzhev, On the Number of Disjoint Pairs of Spermutation Matrices, arXiv:12112:1628 [math.CO], 2012.
Krasimir Yordzhev, On the number of mutually disjoint pairs of Spermutation matrices, Discrete Mathematics 340 (2017) 14421448.


FORMULA

a(n) = A285178(n)*(n!)^(2*n)/2.


CROSSREFS

Cf. A107739, A285178, A285180.
Sequence in context: A076181 A278893 A101355 * A307938 A244190 A013682
Adjacent sequences: A285176 A285177 A285178 * A285180 A285181 A285182


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Apr 14 2017


STATUS

approved



