a(n) = 1 + 1*n + 1*n*2 + 1*n*2*(n-1) + 1*n*2*(n-1)*3 + 1*n*2*(n-1)*3*(n-2) + ... + n!*(n+1)!.
A123637
a(n) = 1 + 1*n + 1*n*2 + 1*n*2*(n-1) + 1*n*2*(n-1)*3 + 1*n*2*(n-1)*3*(n-2) + ... + n!*(n+1)!.
Terms
- a(0) =1a(1) =4a(2) =23a(3) =238a(4) =4285a(5) =120056a(6) =4807699a(7) =259889218a(8) =18207958073
External references
- oeis: A123637