OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
E. D. Krupnikov, K. S. Kölbig, Some special cases of the generalized hypergeometric function (q+1)Fq, J. Comp. Appl. Math. 78 (1997) 79-95.
Wikipedia, Digamma function
FORMULA
Pi = gamma(0,1/4) - gamma(0,3/4) = A020777 - A200134, where gamma(n,x) denotes the generalized Stieltjes constants. - Peter Luschny, May 16 2018
EXAMPLE
Psi(3/4) = -1.085860879786472169626886762817...
MAPLE
evalf(-gamma+Pi/2-3*log(2)) ;
MATHEMATICA
RealDigits[ -PolyGamma[3/4], 10, 97] // First (* Jean-François Alcover, Feb 20 2013 *)
N[StieltjesGamma[0, 3/4], 99] (* Peter Luschny, May 16 2018 *)
PROG
(PARI) -psi(3/4) \\ Charles R Greathouse IV, Nov 22 2011
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); -EulerGamma(R) + Pi(R)/2 - 3*Log(2); // G. C. Greubel, Aug 29 2018
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
R. J. Mathar, Nov 13 2011
STATUS
approved