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

A353009

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

Terms

    a(0) =1a(1) =1a(2) =5a(3) =28a(4) =261a(5) =3153a(6) =46917a(7) =826696a(8) =16824133a(9) =388247185a(10) =10016824133a(11) =285699917796

External references