Number of 0..2 arrays of length n with each element differing from at least one neighbor by something other than 1.

A221567

Number of 0..2 arrays of length n with each element differing from at least one neighbor by something other than 1.

Terms

    a(0) =0a(1) =5a(2) =9a(3) =25a(4) =57a(5) =141a(6) =345a(7) =853a(8) =2097a(9) =5149a(10) =12633a(11) =31013a(12) =76161a(13) =187053a(14) =459369a(15) =1128053a(16) =2770065a(17) =6802301a(18) =16704249a(19) =41020357a(20) =100732833a(21) =247366989a(22) =607452297a(23) =1491704341a(24) =3663139761a(25) =8995478557a(26) =22089965337a(27) =54245756261a(28) =133209897153

External references