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 A091670 Decimal expansion of Gamma(1/4)^4/(4*Pi^3). 8
 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-François 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 August 14 22:45 EDT 2022. Contains 356122 sequences. (Running on oeis4.)