WhittakerM[\[Nu], \[Mu], z] == z^(\[Mu] + 1/2) Sum[Sum[(((-1)^(k - j) 2^(-k + j))/(k - j)!) (Pochhammer[\[Mu] - \[Nu] + 1/2, j]/(Pochhammer[2 \[Mu] + 1, j] j!)), {j, 0, k}] z^k, {k, 0, Infinity}]

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2007-05-02