“K-function”的意思、由来-开放百科全书

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K-function

释义

References
External links

In mathematics, the K-function, typically denoted K(z), is a generalization of the hyperfactorial to complex numbers, similar to the generalization of the factorial to the Gamma function.

Formally, the K-function is defined as

It can also be given in closed form as

where ζ'(z) denotes the derivative of the Riemann zeta function, ζ(a,z) denotes the Hurwitz zeta function and

Another expression using polygamma function is^[1]

Or using balanced generalization of Polygamma function:^[2]

where A is Glaisher constant.

The K-function is closely related to the Gamma function and the Barnes G-function; for natural numbers n, we have

More prosaically, one may write

The first values are

1, 4, 108, 27648, 86400000, 4031078400000, 3319766398771200000, ... ({{OEIS|A002109}}).

References

1. ^Victor S. Adamchik. PolyGamma Functions of Negative Order
2. ^Olivier Espinosa Victor H. Moll. A Generalized polygamma function. Integral Transforms and Special Functions Vol. 15, No. 2, April 2004, pp. 101–115

External links

{{mathworld|title=K-Function|urlname=K-Function}}

1 : Gamma and related functions

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