a(n) = (Lucas(4n) - Lucas(2n))/4.

Terms

a(0) =0a(1) =1a(2) =10a(3) =76a(4) =540a(5) =3751a(6) =25840a(7) =177451a(8) =1217160a(9) =8344876a(10) =57202750a(11) =392089501a(12) =2687463360a(13) =18420257701a(14) =126254611990a(15) =865362736876