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

Author

Andrew Howroyd, Jan 23 2020

Keywords

• nonn

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

• Andrew Howroyd, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A331277, A331638.

Formula

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

a(p) = 2 for prime p.