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

A353015

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

Terms

    a(0) =1a(1) =1a(2) =4a(3) =27a(4) =257a(5) =3157a(6) =47385a(7) =839928a(8) =17168097a(9) =397517868a(10) =10283523826a(11) =293950435376

External references