a(n) = 6*a(n-1) + 4*a(n-2).

Terms

a(0) =0a(1) =1a(2) =6a(3) =40a(4) =264a(5) =1744a(6) =11520a(7) =76096a(8) =502656a(9) =3320320a(10) =21932544a(11) =144876544a(12) =956989440a(13) =6321442816a(14) =41756614656a(15) =275825459200