a(n) = Sum_{k=0..floor(n/2)} n^(3*(n-2*k)) * binomial(n-k,k).

A368890

a(n) = Sum_{k=0..floor(n/2)} n^(3*(n-2*k)) * binomial(n-k,k).

Terms

    a(0) =1a(1) =1a(2) =65a(3) =19737a(4) =16789505a(5) =30525391000

External references