Number of compositions of n with circular differences all equal to 1, 0, or -1.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =11a(5) =15a(6) =27a(7) =43a(8) =68a(9) =116a(10) =189a(11) =311a(12) =519a(13) =860a(14) =1433a(15) =2380a(16) =3968a(17) =6613a(18) =11018a(19) =18374a(20) =30633a(21) =51089a(22) =85208a(23) =142113a(24) =237055a(25) =395409a(26) =659576a(27) =1100262a(28) =1835382a(29) =3061711