a(n) = 7^n mod 6^n.

Terms

a(0) =0a(1) =1a(2) =13a(3) =127a(4) =1105a(5) =1255a(6) =24337a(7) =263671a(8) =725953a(9) =42823a(10) =40610545a(11) =163341463a(12) =780593185a(13) =5464152295a(14) =51309760081a(15) =45711664183