a(n) = Lucas(n) + (-1)^n.

Terms

a(0) =3a(1) =0a(2) =4a(3) =3a(4) =8a(5) =10a(6) =19a(7) =28a(8) =48a(9) =75a(10) =124a(11) =198a(12) =323a(13) =520a(14) =844a(15) =1363a(16) =2208a(17) =3570a(18) =5779a(19) =9348a(20) =15128a(21) =24475a(22) =39604a(23) =64078a(24) =103683a(25) =167760a(26) =271444a(27) =439203a(28) =710648a(29) =1149850