A056079 Number of 7 X 7 binary matrices with n ones, with no zero rows or columns, up to row and column permutation.

1, 2, 15, 79, 420, 1744, 6197, 18715, 50042, 118121, 250025, 475791, 820987, 1287695, 1845875, 2423114, 2923474, 3246721, 3327677, 3150758, 2761802, 2242711, 1690526, 1183725, 771951, 469281, 267108, 142542, 71844, 34271, 15685, 6861, 2948, 1223, 513, 209, 90, 34, 16, 6, 3, 1, 1

Offset

7,2

Comments

Sum_{k=0..49} a(n)=A054976(7).

Links

Table of n, a(n) for n=7..49.

Formula

G.f. : Z(S_7 X S_7; x_1, x_2, ...)-2*Z(S_7 X S_6; x_1, x_2, ...)+Z(S_6 X S_6; 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. A053304.

Sequence in context: A041243 A216247 A291972 * A266622 A036239 A268735

Adjacent sequences: A056076 A056077 A056078 * A056080 A056081 A056082

Keyword

fini,full,nonn

Author

Vladeta Jovovic, Aug 04 2000

Extensions

More terms from Sean A. Irvine, Apr 14 2022

Status

approved