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A056037 Number of 6x6 binary matrices with n ones, with no zero rows or columns, up to row and column permutation. 4
1, 2, 15, 69, 288, 840, 2144, 4488, 8317, 13160, 18636, 23078, 25856, 25623, 23187, 18713, 13932, 9288, 5816, 3256, 1767, 858, 419, 180, 88, 34, 16, 6, 3, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

6,2

COMMENTS

Sum_{k=0..36} a(n)=A054976(6).

LINKS

Table of n, a(n) for n=6..36.

FORMULA

G.f. : Z(S_6 X S_6; x_1, x_2, ...)-2*Z(S_6 X S_5; x_1, x_2, ...)+Z(S_5 X S_5; x_1, x_2, ...) if we replace x_i by 1+x^i, where Z(S_i X S_j; x_1, x_2, ...) is cycle index of Cartesian product of symmetric groups S_i and S_j of degree i and j, respectively.

CROSSREFS

Cf. A052370.

Sequence in context: A216614 A146757 A091135 * A125903 A268644 A178321

Adjacent sequences:  A056034 A056035 A056036 * A056038 A056039 A056040

KEYWORD

fini,full,nonn

AUTHOR

Vladeta Jovovic, Aug 04 2000

STATUS

approved

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Last modified October 20 07:17 EDT 2018. Contains 316378 sequences. (Running on oeis4.)