a(n) is the sum of the first n factorials in decreasing powers from n to 1. a(n) = Sum_{k = 1..n} k!^(n-k+1).

A121945

a(n) is the sum of the first n factorials in decreasing powers from n to 1. a(n) = Sum_{k = 1..n} k!^(n-k+1).

Terms

    a(0) =1a(1) =3a(2) =11a(3) =69a(4) =929a(5) =30273a(6) =2591057a(7) =614059329a(8) =423463272449

External references