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A303170
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Number of ordered ways of writing n as a sum of n tetrahedral numbers.
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4
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1, 1, 1, 1, 5, 21, 61, 141, 309, 757, 2111, 6051, 16721, 44617, 118301, 318501, 871781, 2400741, 6596953, 18067329, 49460555, 135697395, 373271515, 1028451579, 2835353337, 7819016521, 21572619771, 59562583471, 164586609409, 455114644297, 1259191262441, 3485551053561
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OFFSET
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0,5
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LINKS
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FORMULA
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a(n) = [x^n] (Sum_{k>=0} x^(k*(k+1)*(k+2)/6))^n.
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MATHEMATICA
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Table[SeriesCoefficient[Sum[x^(k (k + 1) (k + 2)/6), {k, 0, n}]^n, {x, 0, n}], {n, 0, 31}]
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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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