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A174564 Let J_n be n X n matrix which contains 1's only, I=I_n be the n X n identity matrix and P=P_n be the incidence matrix of the cycle (2,3,...,n,1). Then a(n) is the number of (0,1) n X n matrices A<=J_n-I-P with exactly two 1's in every row and column 5
0, 1, 13, 522, 27828, 1867363 (list; graph; refs; listen; history; text; internal format)



V. S. Shevelev, Development of the rook technique for calculating the cyclic indicators of (0,1)-matrices, Izvestia Vuzov of the North-Caucasus region, Nature sciences 4 (1996), 21-28 (in Russian).

S. E. Grigorchuk, V. S. Shevelev, An algorithm of computing the cyclic indicator of couples discordant permutations with restricted position, Izvestia Vuzov of the North-Caucasus region, Nature sciences 3 (1997), 5-13 (in Russian).


Table of n, a(n) for n=3..8.


Cf. A001499 A007107 A082491 A000186

Sequence in context: A203586 A095883 A139168 * A300525 A295942 A297518

Adjacent sequences: A174561 A174562 A174563 * A174565 A174566 A174567




Vladimir Shevelev, Mar 22 2010



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Last modified December 7 08:24 EST 2022. Contains 358649 sequences. (Running on oeis4.)