A331647 Number of nonnegative integer matrices with 3 columns and any number of distinct nonzero rows with column sums n.

1, 13, 313, 11655, 439779, 14699033, 453027131, 14035890205, 418049781331, 11878976385087, 326859368114097, 8708114475309677, 224507928640721933, 5621130329235752857, 136998397230581620801, 3253556714665728184671, 75415948071516657175683, 1708706073099458659898237

Offset: 0

Author

Andrew Howroyd, Jan 23 2020

Keywords

• nonn

Examples

			The a(1) = 13 matrices are:
  [1 0 0]  [1 0 0]  [0 1 0]  [0 1 0]  [0 0 1]  [0 0 1]
  [0 1 0]  [0 0 1]  [1 0 0]  [0 0 1]  [1 0 0]  [0 1 0]
  [0 0 1]  [0 1 0]  [0 0 1]  [1 0 0]  [0 1 0]  [1 0 0]
.
  [1 1 0]  [1 0 1]  [1 0 0]  [0 1 1]  [0 1 0]  [0 0 1]  [1 1 1]
  [0 0 1]  [0 1 0]  [0 1 1]  [1 0 0]  [1 0 1]  [1 1 0]
		

Crossrefs

Column k=3 of A331568.

Cf. A331646.