a(n) = Sum_{k=0..floor(n/2)} k^n.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =17a(5) =33a(6) =794a(7) =2316a(8) =72354a(9) =282340a(10) =10874275a(11) =53201625a(12) =2438235715a(13) =14350108521a(14) =762963987380