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Search: id:A034323
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| A034323 |
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On half of quintic factorial numbers. |
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+0
11
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| 1, 7, 84, 1428, 31416, 848232, 27143424, 1004306688, 42180880896, 1982501402112, 103090072909824, 5876134155859968, 364320317663318016, 24409461283442307072, 1757481212407846109184, 135326053355404150407168
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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2*a(n) = (5*n-3)(!^5) := product(5*j-3, j=1..n); E.g.f. (-1+(1-5*x)^(-2/5))/2, a(0) := 0.
a(n) ~ 5/2*2^(1/2)*pi^(1/2)*Gamma(2/5)^-1*n^(9/10)*5^n*e^-n*n^n*{1 + 109/300*n^-1 - ...}. - Joe Keane (jgk(AT)jgk.org), Nov 24 2001
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MATHEMATICA
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s=1; lst={s}; Do[s+=n*s; AppendTo[lst, s], {n, 6, 5!, 5}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 08 2008]
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CROSSREFS
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Cf. A008548, A034300, A034301, A034325.
Sequence in context: A099674 A067413 A166178 this_sequence A058795 A027459 A162160
Adjacent sequences: A034320 A034321 A034322 this_sequence A034324 A034325 A034326
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KEYWORD
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easy,nonn
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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