Number of asymmetric Lucas strings of length n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =18a(9) =20a(10) =66a(11) =120a(12) =260a(13) =420a(14) =900a(15) =1408a(16) =2652a(17) =4284a(18) =7676a(19) =12400a(20) =21546a(21) =34584a(22) =58742a(23) =94896a(24) =158400a(25) =255632a(26) =422874a(27) =683144a(28) =1121256a(29) =1812480