A Lucas Jacobsthal product.

Terms

a(0) =2a(1) =1a(2) =9a(3) =20a(4) =77a(5) =231a(6) =774a(7) =2465a(8) =8037a(9) =25916a(10) =84009a(11) =271635a(12) =879382a(13) =2845181a(14) =9208089a(15) =29796580a(16) =96426037a(17) =312037551a(18) =1009780614a(19) =3267709225a(20) =10574544477a(21) =34219920076a(22) =110738027409a(23) =358355719995