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A331644
Number of nonnegative integer matrices with n columns and any number of distinct nonzero rows with column sums 2.
5
1, 1, 13, 313, 14797, 1095601, 119621653, 17943752233, 3550217905597, 894951415465441, 280109128908963493, 106563994919500072153, 48431841090878234155597, 25916389944261925021739281, 16128299505539619187866596533, 11549663940282035980807700520073
OFFSET
0,3
LINKS
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
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 23 2020
STATUS
approved