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Search: id:A047657
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| A047657 |
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Sextuple factorial numbers: product[ k=0..n-1 ] (6*k+2). |
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+0
15
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| 1, 2, 16, 224, 4480, 116480, 3727360, 141639680, 6232145920, 311607296000, 17450008576000, 1081900531712000, 73569236156416000, 5444123475574784000, 435529878045982720000, 37455569511954513920000
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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E.g.f. (1-6*x)^(-1/3)
a(n) = 2^n*A007559(n).
a(n) = A084941(n)/A000142(n)*A000079(n) = 6^n*pochhammer(1/3, n) = 1/2*6^n*GAMMA(n+1/3)*sqrt(3)*GAMMA(2/3)/Pi - Daniel Dockery (peritus(AT)gmail.com) Jun 13, 2003
Let b(n)=b(n-1)+6; then a(n)=b(n)*a(n-1). - Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 17 2008
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MATHEMATICA
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k = 6; b[1] = 2; b[n_] := b[n] = b[n - 1] + k; a[0] = 1; a[1] = 2; a[n_] := a[n] = a[n - 1]*b[n]; Table[a[n], {n, 0, 20}] - Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 17 2008
s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 1, 5!, 6}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 08 2008]
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CROSSREFS
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Cf. A007559, A008542, A011781.
Cf. A000165, A008544, A001813, A047055, A084947, A084948, A084949.
Sequence in context: A012056 A062971 A012164 this_sequence A152542 A152029 A152069
Adjacent sequences: A047654 A047655 A047656 this_sequence A047658 A047659 A047660
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KEYWORD
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nonn,easy
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AUTHOR
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Joe Keane (jgk(AT)jgk.org)
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