a(n) = n! * Sum_{k=0..floor(n/3)} (n - 3*k)^k/(n - 3*k)!.
A356629
a(n) = n! * Sum_{k=0..floor(n/3)} (n - 3*k)^k/(n - 3*k)!.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =25a(5) =121a(6) =361a(7) =5881a(8) =82321a(9) =547345a(10) =6053041a(11) =167991121a(12) =2179469161a(13) =22892967241a(14) =788375451865
External references
- oeis: A356629