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A331637
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Number of binary matrices with nonzero rows, a total of n ones and each column with the same number of ones.
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1
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1, 4, 14, 89, 542, 5156, 47294, 570074, 7103343, 104493608, 1622632574, 28411638982, 526858348382, 10699857854372, 230297862127828, 5330284144906443, 130370767029135902, 3390229775073259800, 92801587319328411134, 2679531116538955252338
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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The a(2) = 4 matrices are:
[1] [1 0] [0 1] [1 1]
[1] [0 1] [1 0]
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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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