Tamás Görbe on X: "Factorial for complex numbers is defined using the gamma function. For n=0,1,2,..., we have Γ(n+1)=n! The previous tweet is a special case of Euler's reflection formula Γ(z)Γ(1-z)=π/sin(πz). https://t.co/jHqZi6j3PD" /
Particular values of the gamma function - Wikipedia