Number of strict compositions of n with all adjacent parts (x, y) satisfying x < 2y and y < 2x.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =1a(7) =3a(8) =3a(9) =5a(10) =5a(11) =5a(12) =9a(13) =7a(14) =13a(15) =15a(16) =17a(17) =19a(18) =29a(19) =31a(20) =39a(21) =43a(22) =63a(23) =59a(24) =75a(25) =121a(26) =119a(27) =169a(28) =167a(29) =199