a(n) is the smallest cube that begins with n^2.

Terms

a(0) =1a(1) =4096a(2) =9261a(3) =166375a(4) =250047a(5) =3652264a(6) =4913a(7) =64a(8) =8120601a(9) =1000a(10) =12167a(11) =1442897a(12) =16974593a(13) =19683a(14) =225866529a(15) =25672375a(16) =28934443a(17) =3241792a(18) =3616805375a(19) =40001688a(20) =4410944a(21) =4843965888a(22) =529475129a(23) =5764224257a(24) =62570773a(25) =676836152