Sum of the cubes of the first n cubefree numbers.

Terms

a(0) =0a(1) =1a(2) =9a(3) =36a(4) =100a(5) =225a(6) =441a(7) =784a(8) =1513a(9) =2513a(10) =3844a(11) =5572a(12) =7769a(13) =10513a(14) =13888a(15) =18801a(16) =24633a(17) =31492a(18) =39492a(19) =48753a(20) =59401a(21) =71568a(22) =87193a(23) =104769a(24) =126721a(25) =151110a(26) =178110a(27) =207901a(28) =243838a(29) =283142