A331644 Number of nonnegative integer matrices with n columns and any number of distinct nonzero rows with column sums 2.

1, 1, 13, 313, 14797, 1095601, 119621653, 17943752233, 3550217905597, 894951415465441, 280109128908963493, 106563994919500072153, 48431841090878234155597, 25916389944261925021739281, 16128299505539619187866596533, 11549663940282035980807700520073

Offset: 0

Author

Andrew Howroyd, Jan 23 2020

Keywords

• nonn

Examples

			The a(2) = 13 matrices are:
   [1 1]  [1 1]  [1 0]  [1 0]  [0 1]  [0 1]
   [1 0]  [0 1]  [1 1]  [0 1]  [1 1]  [1 0]
   [0 1]  [1 0]  [0 1]  [1 1]  [1 0]  [1 1]
.
   [2 1]  [2 0]  [1 2]  [1 0]  [0 2]  [0 1]  [2 2]
   [0 1]  [0 2]  [1 0]  [1 2]  [2 0]  [2 1]
		

Links

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

Crossrefs

Row n=2 of A331568.

Cf. A331645.