Nearest integer to n!/(2*log(2)^(n+1)).

Terms

a(0) =1a(1) =1a(2) =3a(3) =13a(4) =75a(5) =541a(6) =4683a(7) =47293a(8) =545835a(9) =7087261a(10) =102247563a(11) =1622632573a(12) =28091567595a(13) =526858348381