A331649 Number of binary matrices with n distinct columns and any number of distinct nonzero rows with 2 ones in every column and columns in decreasing lexicographic order.

1, 0, 3, 17, 230, 3264, 60338, 1287062, 31900620, 893284155, 27972470286, 967596779631, 36654913572018, 1509052435744560, 67089897326522970, 3203343744126663616, 163486870943294124046, 8881542959996746368420, 511713241494851800728865, 31165957861936237845310435

Offset: 0

Author

Andrew Howroyd, Jan 24 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.

Examples

			The a(2) = 3 matrices are:
   [1 1]  [1 0]  [1 0]
   [1 0]  [1 1]  [0 1]
   [0 1]  [0 1]  [1 1]
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..200

Crossrefs

Row n=2 of A331569.