Number of compositions (ordered partitions) of n into at least 2 distinct positive parts.

Terms

a(0) =0a(1) =0a(2) =0a(3) =2a(4) =2a(5) =4a(6) =10a(7) =12a(8) =18a(9) =26a(10) =56a(11) =64a(12) =100a(13) =132a(14) =192a(15) =350a(16) =434a(17) =616a(18) =850a(19) =1176a(20) =1554a(21) =2750a(22) =3296a(23) =4756a(24) =6292a(25) =8760a(26) =11304a(27) =15602a(28) =24314a(29) =30460