a(n) = n!*Sum_{i=1..n} (Sum_{j=1..i} (i/j)).

A307642

a(n) = n!*Sum_{i=1..n} (Sum_{j=1..i} (i/j)).

Terms

    a(0) =1a(1) =8a(2) =57a(3) =428a(4) =3510a(5) =31644a(6) =312984a(7) =3380544a(8) =39664080a(9) =502927200a(10) =6858181440a(11) =100135491840

External references