a(n) = Product_{k=0..floor((n - 1)/2)} (n - 2*k)^(n - 2*k).

A271385

a(n) = Product_{k=0..floor((n - 1)/2)} (n - 2*k)^(n - 2*k).

Terms

    a(0) =1a(1) =1a(2) =4a(3) =27a(4) =1024a(5) =84375a(6) =47775744a(7) =69486440625

External references