Number of compositions of n with no consecutive 2's.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =14a(6) =28a(7) =54a(8) =105a(9) =205a(10) =399a(11) =777a(12) =1514a(13) =2949a(14) =5744a(15) =11189a(16) =21795a(17) =42454a(18) =82696a(19) =161083a(20) =313772a(21) =611194a(22) =1190540a(23) =2319043a(24) =4517245a(25) =8799105a(26) =17139705a(27) =33386292a(28) =65032887a(29) =126677032