a(n) = 6*a(n-1) + 9*a(n-2), with a(0)=0, a(1)=1.

Terms

a(0) =0a(1) =1a(2) =6a(3) =45a(4) =324a(5) =2349a(6) =17010a(7) =123201a(8) =892296a(9) =6462585a(10) =46806174a(11) =339000309a(12) =2455257420a(13) =17782547301a(14) =128792600586a(15) =932798529225