a(n) = 2*a(n-1) + 10*a(n-2), with a(0) = 2 and a(1) = 2.

Terms

a(0) =2a(1) =2a(2) =24a(3) =68a(4) =376a(5) =1432a(6) =6624a(7) =27568a(8) =121376a(9) =518432a(10) =2250624a(11) =9685568a(12) =41877376a(13) =180610432a(14) =779994624a(15) =3366093568a(16) =14532133376a(17) =62725202432a(18) =270771738624