The number of compositions of n which cannot be viewed as stacks.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =5a(7) =17a(8) =49a(9) =126a(10) =303a(11) =694a(12) =1536a(13) =3312a(14) =7009a(15) =14619a(16) =30164a(17) =61732a(18) =125568a(19) =254246a(20) =513048a(21) =1032696a(22) =2074875a(23) =4163256a(24) =8345605a(25) =16717996a(26) =33473334a(27) =66998380a(28) =134067959a(29) =268233386