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A128152
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Numerator of Sum_{k=0..n} 1/C(n,k)^4.
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0
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1, 2, 33, 164, 20825, 10017, 25940593, 34743416, 3074035689, 672229195, 13443874324243, 431453199593, 53678600587865227, 33768054132971557, 813464644344955, 748569723383876272, 67454811525665973337193
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| p^k divides a(p^k-1) for prime p and integer k>0. p divides a(p-2) for prime p>5.
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LINKS
| Eric Weisstein's World of Mathematics, Binomial Sums.
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FORMULA
| a(n) = Numerator[ Sum[ 1 / binomial[n,k]^4, {k,0,n} ] ].
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MATHEMATICA
| Table[ Numerator[ Sum[ 1 / Binomial[n, k]^4, {k, 0, n} ] ], {n, 0, 50} ]
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CROSSREFS
| Cf. A046825 = Numerator of Sum_{k=0..n} 1/C(n, k). Cf. A100516 = Numerator of Sum_{k=0..n} 1/C(n, k)^2. Cf. A100518 = Numerator of Sum_{k=0..n} 1/C(n, k)^3.
Sequence in context: A041127 A097978 A156369 * A052403 A006558 A002561
Adjacent sequences: A128149 A128150 A128151 * A128153 A128154 A128155
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KEYWORD
| frac,nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), May 10 2007
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