a(n) = 3*a(n-1) + 5*a(n-2), with a(0)=1, a(1)=2.

Terms

a(0) =1a(1) =2a(2) =11a(3) =43a(4) =184a(5) =767a(6) =3221a(7) =13498a(8) =56599a(9) =237287a(10) =994856a(11) =4171003a(12) =17487289a(13) =73316882a(14) =307387091a(15) =1288745683a(16) =5403172504a(17) =22653245927a(18) =94975600301a(19) =398193030538