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

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]

Crossrefs

Column k=3 of A331572.

Cf. A331711.

Sequence in context: A126754 A264820 A194534 * A026586 A298064 A298713

Adjacent sequences: A331709 A331710 A331711 * A331713 A331714 A331715

Keyword

nonn

Author

Andrew Howroyd, Jan 25 2020

Status

approved