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

A350366

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

Terms

    a(0) =1a(1) =2a(2) =18a(3) =312a(4) =8000a(5) =271770a(6) =11502162a(7) =583036832a(8) =34437042432

External references