Tricomi function

Another name for the confluent hypergeometric function of the second kind, defined by G(a|c|z) = e^(i π a) (Γ(c))/(Γ(a)){(Γ(1 - c))/(Γ(1 - a))[e^(-π c) + (sin[π(a - c)])/(sin(π a))]×_1 F_1(a;c;z) - 2(Γ(c - 1))/(Γ(c - a)) z^(1 - c) _1 F_1(a - c + 1;2 - c;z)}, where Γ(x) is the gamma function and _1 F_1(a;b;z) is the confluent hypergeometric function of the first kind.