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

Terms

a(0) =2a(1) =3a(2) =12a(3) =33a(4) =102a(5) =303a(6) =912a(7) =2733a(8) =8202a(9) =24603a(10) =73812a(11) =221433a(12) =664302a(13) =1992903a(14) =5978712a(15) =17936133a(16) =53808402a(17) =161425203a(18) =484275612a(19) =1452826833a(20) =4358480502a(21) =13075441503a(22) =39226324512a(23) =117678973533a(24) =353036920602