Horadam sequence (0,1,9,3).

Terms

a(0) =0a(1) =1a(2) =18a(3) =81a(4) =405a(5) =1944a(6) =9477a(7) =45927a(8) =223074a(9) =1082565a(10) =5255361a(11) =25509168a(12) =123825753a(13) =601059771a(14) =2917611090a(15) =14162371209a(16) =68745613437a(17) =333698181192