Number of compositions (ordered partitions) of n into parts not greater than n/2.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =5a(5) =8a(6) =24a(7) =44a(8) =108a(9) =208a(10) =464a(11) =912a(12) =1936a(13) =3840a(14) =7936a(15) =15808a(16) =32192a(17) =64256a(18) =129792a(19) =259328a(20) =521472a(21) =1042432a(22) =2091008a(23) =4180992a(24) =8375296a(25) =16748544a(26) =33525760a(27) =67047424a(28) =134156288a(29) =268304384