a(1) = 1, a(n) = Sum_{d | n and d < n} a(d)^2 for n > 1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =3a(6) =1a(7) =6a(8) =2a(9) =3a(10) =1a(11) =16a(12) =1a(13) =3a(14) =3a(15) =42a(16) =1a(17) =16a(18) =1a(19) =16a(20) =3a(21) =3a(22) =1a(23) =308a(24) =2a(25) =3a(26) =6a(27) =16a(28) =1a(29) =31