GammaRegularized[a, z] \[Proportional] 1 - ((a^(-(1/2) - a) E^(a - z) z^a)/Sqrt[2 Pi]) (1 + (-1 + 12 z)/(12 a) + (1 - 312 z + 288 z^2)/(288 a^2) + O[1/a^3]) /; (Abs[a] -> Infinity)

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2007-05-02