a(n)-th squarefree is sum of first k squarefrees for some k.

Terms

a(0) =1a(1) =3a(2) =5a(3) =8a(4) =12a(5) =22a(6) =36a(7) =55a(8) =77a(9) =102a(10) =133a(11) =169a(12) =187a(13) =248a(14) =296a(15) =320a(16) =343a(17) =395a(18) =483a(19) =547a(20) =652a(21) =768a(22) =809a(23) =851a(24) =893a(25) =935a(26) =1023a(27) =1065a(28) =1158a(29) =1206