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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.
2
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
0,3
EXAMPLE
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.
Sequence in context: A325717 A291942 A071609 * A068501 A048071 A320996
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Oct 14 2024
STATUS
approved