PolyGamma[z] \[Proportional] Log[z] - 1/(2 z) - (1/(12 z^2)) (1 + O[1/z^2]) + I Pi (-1 + I Cot[Pi z]) Floor[Abs[Arg[z]]/Pi] /; !(Element[z, Integers] && z < 0) && (Abs[z] -> Infinity)

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2007-05-02