a(1) = 1; a(n+1) = Sum_{d|n, n/d odd} a(d)^(n/d).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =3a(6) =4a(7) =5a(8) =5a(9) =7a(10) =8a(11) =9a(12) =17a(13) =18a(14) =19a(15) =29a(16) =29a(17) =30a(18) =58a(19) =59a(20) =91a(21) =157a(22) =158a(23) =159a(24) =284a(25) =317a(26) =318a(27) =445a(28) =573a(29) =574