a(n) = n! * Sum_{k=0..floor(n/2)} (-n/2)^k * binomial(n-k,k)/(n-k)!.

A362276

a(n) = n! * Sum_{k=0..floor(n/2)} (-n/2)^k * binomial(n-k,k)/(n-k)!.

Terms

    a(0) =1a(1) =1a(2) =-1a(3) =-8a(4) =25a(5) =326a(6) =-1709a(7) =-31016a(8) =228257a(9) =5311900a(10) =-50337449a(11) =-1429574464a(12) =16573668409a(13) =555724876552

External references