They are series of the form ζ(F,s) = ∑(a,n)=1 F(n)/n^s, where s is a complex variable, F is a modular form, and (a,n) is the greatest common divisor of a and n.
They are series of the form ζ(F,s) = ∑(a,n)=1 F(n)/n^s, where s is a complex variable, F is a modular form, and (a,n) is the greatest common divisor of a and n.