a(0) = 5, a(1) = 2; for n>1, a(n) = 2*a(n-1) + a(n-2).

Terms

a(0) =5a(1) =2a(2) =9a(3) =20a(4) =49a(5) =118a(6) =285a(7) =688a(8) =1661a(9) =4010a(10) =9681a(11) =23372a(12) =56425a(13) =136222a(14) =328869a(15) =793960a(16) =1916789a(17) =4627538a(18) =11171865a(19) =26971268a(20) =65114401a(21) =157200070a(22) =379514541a(23) =916229152a(24) =2211972845a(25) =5340174842a(26) =12892322529a(27) =31124819900a(28) =75141962329a(29) =181408744558