A331644 - OEIS

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

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OFFSET

0,3

LINKS

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

EXAMPLE

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]

CROSSREFS

Row n=2 of A331568.

Cf. A331645.

Sequence in context: A360324 A241022 A331647 * A052114 A305143 A132485

Adjacent sequences: A331641 A331642 A331643 * A331645 A331646 A331647

KEYWORD

nonn

AUTHOR

Andrew Howroyd, Jan 23 2020

STATUS

approved