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A134356 a(n) = Product_{k=1..n-1} (3k+1)!/(n+k)!. 0
1, 4, 42, 1008, 51480, 5353920, 1100473920, 437480709120, 330886851724800, 470053968773760000, 1241242628123282400000, 6040838558884497984000000, 53797620867616662708672000000, 871394214986903051252166758400000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

FORMULA

a(n) ~ Pi^(5/6) * 3^(3*n^2/2 - 7/36) * n^(n + 13/36) / (A^(1/3) * Gamma(1/3)^(2/3) * 2^(2*n^2 - 11/12) * exp(n - 1/36)), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Oct 26 2017

MATHEMATICA

a = {}; Do[k = Product[(3i + 1)!/(n + i)!, {i, 1, n - 1}]; AppendTo[a, k], {n, 1, 20}]; a

Table[Product[(3k+1)!/(n+k)!, {k, n-1}], {n, 20}] (* Harvey P. Dale, Sep 30 2015 *)

CROSSREFS

Cf. A005130.

Sequence in context: A267616 A243809 A220180 * A156479 A111829 A200000

Adjacent sequences:  A134353 A134354 A134355 * A134357 A134358 A134359

KEYWORD

nonn

AUTHOR

Artur Jasinski, Oct 22 2007

STATUS

approved

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Last modified February 23 18:54 EST 2018. Contains 299586 sequences. (Running on oeis4.)