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Search: id:A069121
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| 0, 2, 96, 1620, 17920, 157500, 1197504, 8240232, 52715520, 318995820, 1847560000, 10328229912, 56073378816, 297051536600, 1541119305600, 7852824450000, 39392404439040, 194905125100620, 952671403252800
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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J. M. Borwein and P. B. Borwein, Pi and the AGM, Wiley, 1987, p. 386.
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FORMULA
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sum(n=1, inf, 1/a(n))=17*Pi^4/3240 (Comtet, 1974)
a(n)=a(n-1)(4n-2)n^3/(n-1)^4, n>1. - Michael Somos, Apr 18 2003
Equals A002736*n^2. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 28 2006
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MAPLE
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with(combinat):for n from 0 to 18 do printf(`%d, `, n^3*sum(binomial(2*n, n), k=1..n)) od: - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 13 2007
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PROGRAM
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(PARI) a(n)=if(n<1, 0, n^4*binomial(2*n, n))
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CROSSREFS
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Sequence in context: A042057 A137322 A158980 this_sequence A157065 A123115 A119696
Adjacent sequences: A069118 A069119 A069120 this_sequence A069122 A069123 A069124
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 07 2002
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