Number of length n 0..2 arrays with no pair in any consecutive three terms totalling exactly 2.

Terms

a(0) =1a(1) =3a(2) =6a(3) =8a(4) =12a(5) =18a(6) =26a(7) =38a(8) =56a(9) =82a(10) =120a(11) =176a(12) =258a(13) =378a(14) =554a(15) =812a(16) =1190a(17) =1744a(18) =2556a(19) =3746a(20) =5490a(21) =8046a(22) =11792a(23) =17282a(24) =25328a(25) =37120a(26) =54402a(27) =79730a(28) =116850a(29) =171252