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A091670 Decimal expansion of Gamma(1/4)^4/(4*Pi^3). 7
1, 3, 9, 3, 2, 0, 3, 9, 2, 9, 6, 8, 5, 6, 7, 6, 8, 5, 9, 1, 8, 4, 2, 4, 6, 2, 6, 0, 3, 2, 5, 3, 6, 8, 2, 4, 2, 6, 5, 7, 4, 8, 1, 2, 1, 7, 5, 1, 5, 6, 1, 7, 8, 7, 8, 9, 7, 4, 2, 8, 1, 6, 3, 1, 8, 8, 0, 3, 2, 4, 0, 1, 2, 5, 7, 5, 0, 3, 6, 6, 3, 0, 6, 7, 8, 6, 4, 7, 3, 2, 9, 8, 5, 7, 8, 0, 9, 5, 5, 5, 9, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Watson's first triple integral.

This is also the value of F. Morley's series from 1902 Sum_{k=0..n} (risefac(k,1/2)/k!)^3 = hypergeometric([1/2,1/2,1/2],[1,1],1) with the rising factorial risefac(n,x). See A277232, also for the Hardy reference and a MathWorld link. - Wolfdieter Lang, Nov 11 2016

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

A. M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 256, 6.1.17 , p. 557, 15.1.26.

M. L. Glasser, I. J. Zucker, Extended Watson integrals for the cubic lattices, Proc. Nat. Acad. Sci., Vol. 74, No. 5 (1977), p. 1800-1801.

Tito Piezas III, Watson's triple integrals.

Eric Weisstein's World of Mathematics, Watson's Triple Integrals.

I. J. Zucker, 70+years of the Watson integrals, J. Stat. Phys., Vol. 145, No. 3 (2011), pp. 591-612.

FORMULA

From Joerg Arndt, Nov 27 2010: (Start)

Equals 1/agm(1,sqrt(1/2))^2.

Equals Gamma(1/4)^4 / (4*Pi^3) = Pi / (Gamma(3/4))^4 = hypergeom([1/2,1/2],[1],1/2)^2, see the two Abramowitz - Stegun references. (End)

Equals the square of A175574. Equals A000796/A068465^4. - R. J. Mathar, Jun 17 2016

Equals hypergeom([1/2,1/2,1/2],[1,1],1) - Wolfdieter Lang, Nov 12 2016

Equals Sum_{k>=0) binomial(2*k,k)^3/2^(6*k). - Amiram Eldar, Aug 26 2020

EXAMPLE

1.39320392968567685918424626032536824265748121751561787897...

MAPLE

Pi/GAMMA(3/4)^4 ; evalf(%) ; # R. J. Mathar, Jun 17 2016

MATHEMATICA

RealDigits[ N[ Gamma[1/4]^4/(4*Pi^3), 102]][[1]] (* Jean-Fran├žois Alcover, Nov 12 2012, after Eric W. Weisstein *)

PROG

(PARI) 1/agm(sqrt(1/2), 1)^2 \\ Charles R Greathouse IV, Mar 03 2016

(MAGMA) SetDefaultRealField(RealField(100)); R:= RealField(); Gamma(1/4)^4/(4*Pi(R)^3); // G. C. Greubel, Oct 26 2018

CROSSREFS

Cf. A091671, A091672, A277232, A293238 (inverse).

Sequence in context: A336501 A016674 A264918 * A201416 A072560 A290506

Adjacent sequences:  A091667 A091668 A091669 * A091671 A091672 A091673

KEYWORD

nonn,cons

AUTHOR

Eric W. Weisstein, Jan 27 2004

STATUS

approved

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Last modified September 24 06:13 EDT 2021. Contains 347623 sequences. (Running on oeis4.)