BesselY[n, z] \[Proportional] (2/(Pi n!)) Log[z/2] (z/2)^n (1 - z^2/(4 (n + 1)) + z^4/(32 (n + 1) (n + 2)) + \[Ellipsis]) - (((n - 1)!/Pi) (1 + (1/(4 (n - 1))) z^2 + (1/(32 (n - 1) (n - 2))) z^4 + \[Ellipsis]))/(z/2)^n - (1/(Pi n!)) (z/2)^n (-EulerGamma + PolyGamma[1 + n] - ((1 - EulerGamma + PolyGamma[2 + n])/ (4 (n + 1))) z^2 + ((3/2 - EulerGamma + PolyGamma[3 + n])/ (32 (n + 1) (n + 2))) z^4 + \[Ellipsis]) /; (z -> 0) && Element[n - 3, Integers] && n - 3 >= 0

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2007-05-02