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A285179 Number of disjoint non-ordered pairs of n^2 X n^2 S-permutation matrices. 2
0, 56, 419250816, 2294248126968596791296, 71871209790288983974921874964480000000000, 70222282105561329499166350697268240329817049897201827840000000000000 (list; graph; refs; listen; history; text; internal format)
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: 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

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Last modified August 3 13:49 EDT 2020. Contains 336198 sequences. (Running on oeis4.)