a(n) = 6*a(n-1) + 3*a(n-2), a(0)=2, a(1)=14.

Terms

a(0) =2a(1) =14a(2) =90a(3) =582a(4) =3762a(5) =24318a(6) =157194a(7) =1016118a(8) =6568290a(9) =42458094a(10) =274453434a(11) =1774094886a(12) =11467929618a(13) =74129862366a(14) =479182963050