A377061 Number of inequivalent n X 3 nonnegative integer arrays with row sums 3 and column sums n up to permutations of rows and columns.

1, 1, 2, 5, 9, 14, 28, 44, 73, 118, 184, 276, 422, 610, 880, 1248, 1742, 2383, 3250, 4341, 5758, 7550, 9808, 12600, 16103, 20352, 25572, 31890, 39519, 48620, 59548, 72432, 87703, 105629, 126642, 151077, 179572, 212428, 250408, 294024, 344052, 401106, 466260, 540110, 623908

Offset: 0

Author

Andrew Howroyd, Oct 14 2024

Keywords

• nonn

Examples

			The a(2) = 2 matrices are:
  [2 1 0]   [1 1 1]
  [0 1 2]   [1 1 1]
.
The a(3) = 5 matrices are:
  [3 0 0]   [3 0 0]   [2 1 0]   [2 1 0]   [1 1 1]
  [0 3 0]   [0 2 1]   [1 1 1]   [1 0 2]   [1 1 1]
  [0 0 3]   [0 1 2]   [0 1 2]   [0 2 1]   [1 1 1]
		

Crossrefs

Column k=3 of A377060.

Cf. A172743, A377062.