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

Author

Andrew Howroyd, Jan 25 2020

Keywords

• nonn

Comments

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

Examples

			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.