a(n) = a(floor(n/2)) + a(floor(n/3)) + a(floor(n/6)), with a(0) = 1.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =9a(5) =9a(6) =15a(7) =15a(8) =17a(9) =19a(10) =19a(11) =19a(12) =29a(13) =29a(14) =29a(15) =29a(16) =31a(17) =31a(18) =41a(19) =41a(20) =41a(21) =41a(22) =41a(23) =41a(24) =55a(25) =55a(26) =55a(27) =57a(28) =57a(29) =57