n! in base 6.

Terms

a(0) =1a(1) =1a(2) =2a(3) =10a(4) =40a(5) =320a(6) =3200a(7) =35200a(8) =510400a(9) =11440000a(10) =205440000a(11) =3543320000a(12) =115310400000