C7g. Riemann zeta function

Functions
Function	Zeta (X As Double, Optional Info As Long) As Double
	Riemann zeta function ζ(x)
Sub	Zeta_sub (Ret As Double, X As Double, Optional Info As Long)
	Riemann zeta function ζ(x) (Subroutine version)

Detailed Description

This is the group of C7g. Riemann zeta function.