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Search: id:A058407
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| A058407 |
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Number of 3 X n nonnegative integer matrices with all column sums 3, up to row and column permutation. |
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+0
6
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| 1, 3, 13, 44, 134, 356, 876, 1966, 4146, 8236, 15592, 28252, 49357, 83377, 136837, 218728, 341554, 522064, 782810, 1153180, 1671698
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Number of 3 X n nonnegative integer matrices with all column sums equal to m, up to row and column permutation, is coefficient of x^n in expansion of 1 / 6 * (1 / (1 - x)^C(m + 2,2) + 3 / (1 - x)^floor((m + 2) / 2) / (1 - x^2)^(C(m + 2,2) - floor((m + 2) / 2)) / 2 + 2 / (1 - x)^(C(m + 2,2) - 3 * floor(C(m + 2,2) / 3)) / (1 - x^3)^floor(C(m + 2,2) / 3)).
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LINKS
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Number of m x l nonnegative integer matrices with all column sums equal to n, up to row and column permutation
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FORMULA
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G.f.: 1/6*(1/(1-x)^10+3/(1-x)^2/(1-x^2)^4+2/(1-x)/(1-x^3)^3).
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CROSSREFS
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Cf. A050531, A058389, A058408.
Sequence in context: A019008 A062609 A004660 this_sequence A095863 A136520 A058934
Adjacent sequences: A058404 A058405 A058406 this_sequence A058408 A058409 A058410
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 25 2000
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