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Search: id:A004117
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| A004117 |
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Numerators of expansion of (1-x)^{-1/3}. |
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+0
4
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| 1, 1, 2, 14, 35, 91, 728, 1976, 5434, 135850, 380380, 1071980, 9111830, 25933670, 74096200, 637227320, 1832028545, 5280552865, 137294374490, 397431084050, 1152550143745, 10043651252635, 29217894553120
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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(1/n!) * prod(k=0, n-1, 3k+1) * 3^A054861(n). - R. Stephan, Mar 13 2004
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PROGRAM
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(PARI) a(n)=prod(k=1, n, 3*k-2)/n!*3^sum(k=1, n, valuation(k, 3))
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CROSSREFS
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Cf. A004128.
Cf. A004987, A007559, A047657, A054861, A034689, A053101, A072888.
Sequence in context: A145910 A128126 A134647 this_sequence A135706 A091520 A108597
Adjacent sequences: A004114 A004115 A004116 this_sequence A004118 A004119 A004120
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Fixed typo in formula. - Pontus von Broemssen (pontus.von.bromssen(AT)gmail.com), Nov 25 2008
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