A271946 a(n) = Product_{k=0..n} (6*k)!.

1, 720, 344881152000, 2208058019165981638656000000, 1369986068925795885347091500568179543900160000000000, 363392722685428853076589064611759104109572860599125858715484081356800000000000000000

Offset

0,2

Comments

The next term has 126 digits.

Partial products of A195390. - Michel Marcus, Jul 06 2019

Links

Seiichi Manyama, Table of n, a(n) for n = 0..15

Formula

a(n) ~ A^(-1/6) * exp(1/72 - 7*n/2 - 9*n^2/2) * n^(55/72 + 7*n/2 + 3*n^2) * 2^(1/72 + 4*n + 3*n^2) * 3^(47/72 + 7*n/2 + 3*n^2) * Pi^(n/2 - 1/3) * Gamma(1/3)^(5/3), where A = A074962 is the Glaisher-Kinkelin constant.

Mathematica

Table[Product[(6*k)!, {k, 0, n}], {n, 0, 8}]

Prog

(PARI) {a(n) = prod(k=1, n, (6*k)!)} \\ Seiichi Manyama, Jul 06 2019

Crossrefs

Cf. A000178, A098694, A195390, A268504, A268505, A268506, A271947.

Sequence in context: A367570 A294323 A072238 * A172727 A283048 A282021

Adjacent sequences: A271943 A271944 A271945 * A271947 A271948 A271949

Keyword

nonn

Author

Vaclav Kotesovec, Apr 17 2016

Status

approved