Related to the position of the smallest part in all compositions of n.

Terms

a(0) =1a(1) =2a(2) =7a(3) =15a(4) =36a(5) =80a(6) =174a(7) =371a(8) =787a(9) =1644a(10) =3410a(11) =7031a(12) =14423a(13) =29455a(14) =59948a(15) =121656a(16) =246302a(17) =497661a(18) =1003864a(19) =2022143a(20) =4068597a(21) =8178131a(22) =16425116a(23) =32965907a(24) =66125958a(25) =132577442a(26) =265700195a(27) =532313023a(28) =1066152092