A128152 - OEIS

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A128152

Numerator of Sum_{k=0..n} 1/binomial(n,k)^4.

1, 2, 33, 164, 20825, 10017, 25940593, 34743416, 3074035689, 672229195, 13443874324243, 431453199593, 53678600587865227, 33768054132971557, 813464644344955, 748569723383876272, 67454811525665973337193

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OFFSET

0,2

COMMENTS

p^k divides a(p^k-1) for prime p and integer k > 0. p divides a(p-2) for prime p > 5.

LINKS

Table of n, a(n) for n=0..16.

Eric Weisstein's World of Mathematics, Binomial Sums.

FORMULA

a(n) = numerator(Sum_{k=0..n} 1/binomial(n,k)^4).

MATHEMATICA

Table[ Numerator[ Sum[ 1 / Binomial[n, k]^4, {k, 0, n} ] ], {n, 0, 50} ]