La fonsion Gama d'Euler a l'é la fonsion definìa an sël semipian { z ∈ C ∣ R e z > 0 } {\displaystyle \{z\in \mathbb {C} \mid Rez>0\}} a valor an C {\displaystyle \mathbb {C} } da la fórmola Γ ( z ) = ∫ 0 + ∞ t z − 1 e − t d t {\displaystyle \Gamma (z)=\int _{0}^{+\infty }t^{z-1}e^{-t}dt} . Per tuti ij nùmer naturaj n ≥ 1 {\displaystyle n\geq 1} a val la relassion Γ ( n ) = ( n − 1 ) ! {\displaystyle \Gamma (n)=(n-1)!}
