a(n) = floor(n^n / 2^n).

Terms

a(0) =1a(1) =0a(2) =1a(3) =3a(4) =16a(5) =97a(6) =729a(7) =6433a(8) =65536a(9) =756680a(10) =9765625a(11) =139312339a(12) =2176782336a(13) =36972058910a(14) =678223072849