A Gauss-Kummer series is defined, for complex numbers with
, by
|
(1)
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(2)
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(OEIS A056981 and A056982), where
is a hypergeometric function and
is a binomial coefficient. The series can
be derived using Kummer's quadratic
transformation. The Gauss-Kummer series is closely related to the perimeter
of an ellipse.