Replace n with concatenation of its odd divisors >1.

Terms

a(0) =0a(1) =0a(2) =3a(3) =0a(4) =5a(5) =3a(6) =7a(7) =0a(8) =39a(9) =5a(10) =11a(11) =3a(12) =13a(13) =7a(14) =3515a(15) =0a(16) =17a(17) =39a(18) =19a(19) =5a(20) =3721a(21) =11a(22) =23a(23) =3a(24) =525a(25) =13a(26) =3927a(27) =7a(28) =29a(29) =3515