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

A368888

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

Terms

    a(0) =1a(1) =1a(2) =5a(3) =19a(4) =305a(5) =1976a(6) =54613a(7) =494901a(8) =19460545a(9) =226000855a(10) =11535280901a(11) =163226844144

External references