Remove squares!

Terms

a(0) =2a(1) =3a(2) =5a(3) =6a(4) =7a(5) =2a(6) =10a(7) =11a(8) =3a(9) =13a(10) =14a(11) =15a(12) =17a(13) =2a(14) =19a(15) =5a(16) =21a(17) =22a(18) =23a(19) =6a(20) =26a(21) =3a(22) =7a(23) =29a(24) =30a(25) =31a(26) =2a(27) =33a(28) =34a(29) =35