A262261 a(n) = Product_{k=0..n} binomial(4*k,k).

1, 4, 112, 24640, 44844800, 695273779200, 93581069585203200, 110803729631663996928000, 1165466869384731418887782400000, 109720873815210197693149787062272000000, 93006053830822450607559730484293052399616000000

Offset

0,2

Comments

In general, for p > 1, Product_{k=0..n} binomial(p*k,k) ~ A^(1 + 1/(p*(p-1))) * exp(n/2 - 1/12 - 1/(12*p*(p-1))) * n^(-1/3 - n/2 - 1/(12*p*(p-1))) * (p-1)^(1/(12*(p-1)) - p*n/2 - (p-1)*n^2/2) * p^(-1/(12*p) + (p+1)*n/2 + p*n^2/2) * (2*Pi)^(-1/4 - n/2) * Product_{j=1..p-1} (Gamma(j/(p-1))^(j/(p-1)) / Gamma(j/p)^(j/p)), where A = A074962 is the Glaisher-Kinkelin constant.

Links

Table of n, a(n) for n=0..10.

Formula

a(n) ~ A^(13/12) * 2^(9*n/2 + 4*n^2) * exp(n/2 - 13/144) * Gamma(1/4)^(1/2) / (Gamma(1/3)^(1/3) * 3^(11/36 + 2*n + 3*n^2/2) * Pi^(7/12 + n/2) * n^(49/144 + n/2)), where A = A074962 is the Glaisher-Kinkelin constant.

Mathematica

Table[Product[Binomial[4*k, k], {k, 0, n}], {n, 0, 10}]

Crossrefs

Cf. A007685 (p=2), A268196 (p=3).

Cf. A000178, A098694, A268504, A268505, A268506, A271946, A271947.

Cf. A005810, A165975.

Sequence in context: A185320 A293158 A196458 * A085522 A263416 A078780

Adjacent sequences: A262258 A262259 A262260 * A262262 A262263 A262264

Keyword

nonn,easy

Author

Vaclav Kotesovec, Apr 17 2016

Status

approved