a(n) = n*(2*n-1)*a(n-1) + ((n-1)!)^2, with a(0) = 0, n > 0.

A303109

a(n) = n*(2*n-1)*a(n-1) + ((n-1)!)^2, with a(0) = 0, n > 0.

Terms

    a(0) =0a(1) =1a(2) =7a(3) =109a(4) =3088a(5) =139536a(6) =9223776a(7) =839882016a(8) =100811243520

External references