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A331721
Number of nonequivalent n-column nonnegative integer matrices with column sums 4 and any number of nonzero rows up to permutation of rows and columns.
1
1, 5, 66, 1338, 43686, 2142277, 149056260, 13991691663, 1705750869937, 262268740077763, 49694977078927305, 11388565848749818055, 3107918736854019004136, 996840601151518793573156, 371595543159269706775806375, 159437222426663041455988930042, 78072200940916732097886063687252
OFFSET
0,2
CROSSREFS
Row n=4 of A331485.
Sequence in context: A279463 A361409 A367837 * A367847 A209935 A156597
KEYWORD
nonn
AUTHOR
Andrew Howroyd, Jan 31 2020
STATUS
approved