Largest odd divisor of n!.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =3a(5) =15a(6) =45a(7) =315a(8) =315a(9) =2835a(10) =14175a(11) =155925a(12) =467775a(13) =6081075a(14) =42567525a(15) =638512875a(16) =638512875a(17) =10854718875a(18) =97692469875