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A261842
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Number of compositions of n into distinct parts where each part i is marked with a word of length i over a quaternary alphabet whose letters appear in alphabetical order.
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2
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1, 4, 10, 100, 195, 736, 6032, 11712, 35285, 100260, 871386, 1492820, 4438573, 10525720, 29825140, 241360728, 405645867, 1086289116, 2489722574, 6158961820, 14573822743, 123303661384, 192326074572, 504783599080, 1073240557055, 2539006453740, 5337585654950
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OFFSET
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0,2
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COMMENTS
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Also matrices with four rows of nonnegative integers with distinct positive column sums and total element sum n.
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LINKS
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MAPLE
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b:= proc(n, i, p) option remember;
`if`(i*(i+1)/2<n, 0, `if`(n=0, p!, b(n, i-1, p)+
`if`(i>n, 0, b(n-i, i-1, p+1)*binomial(i+3, 3))))
end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..40);
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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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