Number of compositions of n into ceiling(n/2) parts with 1 <= each part <=4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =20a(7) =31a(8) =65a(9) =101a(10) =216a(11) =336a(12) =728a(13) =1128a(14) =2472a(15) =3823a(16) =8451a(17) =13051a(18) =29050a(19) =44803a(20) =100298a(21) =154518a(22) =347568a(23) =534964a(24) =1208220a(25) =1858156a(26) =4211312a(27) =6472168a(28) =14712960a(29) =22597760