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A068467 Decimal expansion of (1/4)! = Gamma(5/4). 8
9, 0, 6, 4, 0, 2, 4, 7, 7, 0, 5, 5, 4, 7, 7, 0, 7, 7, 9, 8, 2, 6, 7, 1, 2, 8, 8, 9, 6, 6, 9, 1, 8, 0, 0, 0, 7, 4, 8, 7, 9, 1, 9, 2, 0, 7, 2, 0, 0, 1, 6, 3, 6, 6, 8, 5, 8, 3, 4, 4, 4, 9, 9, 8, 9, 2, 4, 7, 9, 8, 1, 0, 8, 8, 4, 6, 8, 2, 2, 8, 0, 4, 0, 4, 5, 9, 0, 0, 3, 4, 1, 8, 0, 8, 4, 6, 0, 7, 5, 0, 9, 0, 3, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

J. M. Borwein and I. J. Zucker, Fast evaluation of the gamma function for small rational fractions using complete elliptic integrals of the first kind, IMA Journal of Numerical Analysis, vol. 12, no. 4, pp. 519-526, 1992.

Greg Martin, A product of Gamma function values at fractions with the same denominator, arXiv:0907.4384v1 [math.CA], 24-July-2009

Albert Nijenhuis, Small Gamma Products with Simple Values, arXiv:0907.1689v1 [math.CA], 9-July-2009.

Raimundas Vidunas, Expressions for values of the gamma function, arXiv:math/0403510 [math.CA], 30-March-2004.

Wikipedia, Particular values of the Gamma function

Index to sequences related to the Gamma function

FORMULA

2^(3/4)*(2/e^(16*Pi) + 1)* Pi^(3/4)/(2^(13/16)/(sqrt(2) - 1)^(1/4) + 2^(1/4) + 1) is a very good approximation (~88 digits) which becomes exact if you replace (2/e^(16*Pi) + 1) by EllipticTheta[3,0,exp(-(16*Pi))]. [R. W. Gosper, Posting to Math Fun Mailing List, Dec 27 2011.]

Equals A068466 /4 . - R. J. Mathar, Jan 10 2013

Also equals integral_{0..oo} exp(-x^4) dx. - Jean-François Alcover, Mar 29 2013

Equals 2^(-5/4)*Pi^(3/4)*Product_{k>=1} tanh(Pi*k/2). - Keshav Raghavan, Aug 25 2016

EXAMPLE

0.906402477055477077982671288966918000748791920720...

MAPLE

evalf(GAMMA(5/4)) ; # R. J. Mathar, Jan 10 2013

MATHEMATICA

RealDigits[Gamma[5/4], 10, 120][[1]] (* Harvey P. Dale, Aug 23 2013 *)

PROG

(PARI) gamma(5/4) \\ Altug Alkan, Sep 18 2016

(MAGMA) SetDefaultRealField(RealField(100)); Gamma(5/4); // G. C. Greubel, Mar 11 2018

CROSSREFS

Cf. A202623.

Sequence in context: A199789 A019874 A197520 * A131223 A225464 A296566

Adjacent sequences:  A068464 A068465 A068466 * A068468 A068469 A068470

KEYWORD

cons,easy,nonn

AUTHOR

Benoit Cloitre, Mar 10 2002

EXTENSIONS

Removed leading zero and adjusted offset, R. J. Mathar, Feb 06 2009

Additional reference from Joerg Arndt, Dec 28 2011

Edited by N. J. A. Sloane, Dec 28 2011

STATUS

approved

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Last modified March 21 22:19 EDT 2019. Contains 321382 sequences. (Running on oeis4.)