A331639 Number of binary matrices with nonzero rows, a total of n ones and distinct columns each with the same number of ones and columns in decreasing lexicographic order.

1, 2, 2, 8, 2, 95, 2, 1062, 2651, 17667, 2, 946585, 2, 10422801, 126470568, 555727036, 2, 61345560608, 2, 1559456567421, 28383861400820, 19815939349521, 2, 30118264353296169, 8755909495925859, 49334805652369611, 21097628287362414244, 98053701052228556867, 2, 27303813269345643163251

Offset

1,2

Comments

The condition that the columns be in decreasing order is equivalent to considering nonequivalent matrices with distinct columns up to permutation of columns.

Links

Table of n, a(n) for n=1..30.

Formula

a(n) = Sum_{d|n} A331277(n/d, d).

a(p) = 2 for prime p.

Crossrefs

Cf. A331277, A331638.

Sequence in context: A274139 A283995 A056189 * A079242 A121860 A283990

Adjacent sequences: A331636 A331637 A331638 * A331640 A331641 A331642

Keyword

nonn

Author

Andrew Howroyd, Jan 23 2020

Status

approved