a(n) = Sum_{r=0..n-1} Sum_{s=r+1..n} s! * r^(n-s).
A190194
a(n) = Sum_{r=0..n-1} Sum_{s=r+1..n} s! * r^(n-s).
Terms
- a(0) =0a(1) =1a(2) =4a(3) =20a(4) =116a(5) =776a(6) =5912a(7) =50648a(8) =482552a(9) =5065016a(10) =58099832a(11) =723315128a(12) =9715154552a(13) =140051879096
External references
- oeis: A190194