OFFSET
0,1
FORMULA
Equals (sqrt(2)+1)*Pi/2 - sqrt(2)*arcsinh(1) - 4*log(2) - gamma, where gamma is Euler's constant (A001620). - Amiram Eldar, Jun 03 2022
EXAMPLE
psi(7/8) = -0.80401707154769...
MATHEMATICA
RealDigits[PolyGamma[7/8], 10, 100][[1]] (* Amiram Eldar, Jun 03 2022 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
R. J. Mathar, Jun 01 2022
STATUS
approved