a(n) = n! mod 3^n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =6a(4) =24a(5) =120a(6) =720a(7) =666a(8) =954a(9) =8586a(10) =26811a(11) =58725a(12) =173259a(13) =1189485a(14) =3898206a(15) =1077462a(16) =17239392a(17) =34789338a(18) =238787595a(19) =275338926a(20) =2019994119a(21) =578463687a(22) =2265847911a(23) =52114501953a(24) =121029900948a(25) =201452158890