A285179 Number of disjoint non-ordered pairs of n^2 X n^2 S-permutation matrices.

0, 56, 419250816, 2294248126968596791296, 71871209790288983974921874964480000000000, 70222282105561329499166350697268240329817049897201827840000000000000

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 S-permutation Matrices, arXiv:12112:1628 [math.CO], 2012.

Krasimir Yordzhev, On the number of mutually disjoint pairs of S-permutation matrices, Discrete Mathematics 340 (2017) 1442-1448.

Formula

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

Crossrefs

Cf. A107739, A285178, A285180.

Sequence in context: A278893 A375778 A101355 * A307938 A244190 A013682

Adjacent sequences: A285176 A285177 A285178 * A285180 A285181 A285182

Keyword

nonn

Author

N. J. A. Sloane, Apr 14 2017

Status

approved