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

0,2

Links

Table of n, a(n) for n=0..17.

Example

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.

Sequence in context: A217674 A360324 A241022 * A331644 A052114 A305143

Adjacent sequences: A331644 A331645 A331646 * A331648 A331649 A331650

Keyword

nonn

Author

Andrew Howroyd, Jan 23 2020

Status

approved