a(n) = 6^n-5^n+1^n.

Terms

a(0) =1a(1) =2a(2) =12a(3) =92a(4) =672a(5) =4652a(6) =31032a(7) =201812a(8) =1288992a(9) =8124572a(10) =50700552a(11) =313968932a(12) =1932641712a(13) =11839990892a(14) =72260648472a(15) =439667406452