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

Terms

a(0) =1a(1) =2a(2) =14a(3) =38a(4) =206a(5) =662a(6) =3134a(7) =11078a(8) =48686a(9) =181622a(10) =765854a(11) =2945318a(12) =12135566a(13) =47479382a(14) =193106174a(15) =762858758a(16) =3080132846a(17) =12234437942a(18) =49196032094a(19) =196009287398a(20) =786361672526