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A166750 a(n)=(A001147(n))^3=2^(3*n)*GAMMA(n+1/2)^3/Pi^(3/2),n=0,1... . 0
1, 1, 27, 3375, 1157625, 843908625, 1123242379875, 2467763508585375, 8328701841475640625, 40918912147169822390625, 280662818417437811777296875 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

FORMULA

G.f.:sum(a(n)*x^n/(n!)^3,n=0..infinity)=

4*EllipticK((1/2)*sqrt(2-2*sqrt(1-8*x)))^2/Pi^2,

sum(a(n)*x^n/(n!)^4,n=0..infinity)=hypergeom([1/2,1/2,1/2],[1,1,1],8*x).

Asymptotics:a(n)=(2*sqrt(2)/((exp(-1/2))^3*(exp(1/2))^3)-(1/4)*sqrt(2)/

((exp(-1/2))^3*(exp(1/2))^3*n)+(1/64)*sqrt(2)/((exp(-1/2))^3*

(exp(1/2))^3*n^2)+O(1/n^3))*(2^n)^3/(((1/n)^n)^3*(exp(n))^3),n->infinity.

Integral representation as n-th moment of a positive function on a positive

halfaxis (solution of the Stieltjes moment problem),in Maple notation:

a(n)=int(x^n*MeijerG([[],[]],[[ -1/2,-1/2,-1/2],[]],x/8)/(8*(Pi)^(3/2)),

x=0..infinity), n=0,1... .

This solution is not unique.

MAPLE

Maple: a(n)=(doublefactorial(2*n-1))^3, n=0, 1... .

CROSSREFS

Sequence in context: A017559 A069076 A128507 * A195374 A046367 A059795

Adjacent sequences:  A166747 A166748 A166749 * A166751 A166752 A166753

KEYWORD

nonn

AUTHOR

Karol A. Penson (penson(AT)lptl.jussieu.fr), Oct 21 2009

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Last modified February 13 22:17 EST 2012. Contains 205566 sequences.