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A331708
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Number of nonnegative integer matrices with distinct nonzero rows, total sum n, distinct columns with equals sums and columns in decreasing lexicographic order.
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1
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1, 2, 4, 10, 6, 100, 14, 832, 1928, 9280, 66, 409928, 134, 3138847, 32173339, 134531629, 618, 9353244335, 1178, 183394485615, 2395983801112, 2311773448717, 4758, 1479147860804022, 311353753955807, 3599356750729620, 613047176698674761, 1842753685676233794, 30462
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OFFSET
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1,2
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COMMENTS
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The condition that the columns be in decreasing order is equivalent to considering nonequivalent matrices with distinct columns up to permutation of columns.
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LINKS
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FORMULA
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EXAMPLE
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The a(4) = 10 matrices are:
[1 0 0 0] [1 1] [1 0] [1 0]
[0 1 0 0] [1 0] [1 1] [0 1]
[0 0 1 0] [0 1] [0 1] [1 1]
[0 0 0 1]
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[2 1] [2 0] [1 0] [3] [1] [4]
[0 1] [0 2] [1 2] [1] [3]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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