Number of integer compositions of n that are the first sums of some composition.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =7a(7) =12a(8) =16a(9) =27a(10) =36a(11) =59a(12) =79a(13) =127a(14) =170a(15) =270a(16) =361a(17) =568a(18) =759a(19) =1185a(20) =1583a(21) =2456a(22) =3280a(23) =5063a(24) =6760a(25) =10391a(26) =13871a(27) =21247a(28) =28358a(29) =43310