a(n)=4a(n-1)+C(n+4,4),n>0, a(0)=1.

Terms

a(0) =1a(1) =9a(2) =51a(3) =239a(4) =1026a(5) =4230a(6) =17130a(7) =68850a(8) =275895a(9) =1104295a(10) =4418181a(11) =17674089a(12) =70698176a(13) =282795084a(14) =1131183396a(15) =4524737460a(16) =18098954685a(17) =72395824725a(18) =289583306215