a(n) = 2*a(n-1) + 12*a(n-2).

Terms

a(0) =1a(1) =2a(2) =16a(3) =56a(4) =304a(5) =1280a(6) =6208a(7) =27776a(8) =130048a(9) =593408a(10) =2747392a(11) =12615680a(12) =58200064a(13) =267788288a(14) =1233977344a(15) =5681414144a(16) =26170556416a(17) =120518082560a(18) =555082842112