a(n) = Sum_{k=1..n} C(n-k, floor((n-k)/k)).

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =5a(5) =7a(6) =13a(7) =19a(8) =34a(9) =61a(10) =108a(11) =174a(12) =384a(13) =641a(14) =1166a(15) =2337a(16) =4458a(17) =7828a(18) =16421a(19) =29346a(20) =57231a(21) =114126a(22) =215915a(23) =396491a(24) =839324a(25) =1549146a(26) =2983185a(27) =5978656a(28) =11628952a(29) =21812113