a(n) = n! * Sum_{k=0..floor(n/3)} k^(n - 3*k)/k!.
A355575
a(n) = n! * Sum_{k=0..floor(n/3)} k^(n - 3*k)/k!.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =6a(4) =24a(5) =120a(6) =1080a(7) =10080a(8) =120960a(9) =1874880a(10) =34473600a(11) =738460800a(12) =17982518400a(13) =489858969600
External references
- oeis: A355575