a(n) = [x^n] Product_{k=0..n} (1 + k*x)^3.

A384012

a(n) = [x^n] Product_{k=0..n} (1 + k*x)^3.

Terms

    a(0) =1a(1) =3a(2) =33a(3) =630a(4) =17247a(5) =616770a(6) =27264976a(7) =1436603616a(8) =87922855935

External references