A331712 - OEIS

A331712

Number of nonnegative integer matrices with 3 columns and any number of distinct nonzero rows with column sums n and columns in nonincreasing lexicographic order.

1, 4, 59, 1987, 73567, 2451082, 75511809, 2339355873, 69675164655, 1979830442230, 54476566524395, 1451352437084341, 37417988223257669, 936855055418767566, 22833066207602691971, 542259452455606556087, 12569324678636155802527, 284784345516796080566156, 6313245421004111720679497

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OFFSET

0,2

COMMENTS

The condition that the columns be in nonincreasing order is equivalent to considering nonequivalent matrices up to permutation of columns.

LINKS

Table of n, a(n) for n=0..18.

EXAMPLE

The a(1) = 4 matrices are:

[1 0 0] [1 1 0] [1 0 0] [1 1 1]

[0 1 0] [0 0 1] [0 1 1]

[0 0 1]