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

Terms

a(0) =0a(1) =1a(2) =3a(3) =7a(4) =15a(5) =26a(6) =54a(7) =85a(8) =159a(9) =292a(10) =513a(11) =804a(12) =1844a(13) =2965a(14) =5169a(15) =10679a(16) =20107a(17) =34120a(18) =72498a(19) =126028a(20) =245966a(21) =498852a(22) =913872a(23) =1644570a(24) =3600916a(25) =6530881a(26) =12280999a(27) =25149973a(28) =48355605a(29) =89310576