Cubes that become prime when their most significant (or leftmost) digit is removed.

Terms

a(0) =27a(1) =343a(2) =729a(3) =1331a(4) =2197a(5) =6859a(6) =29791a(7) =50653a(8) =59319a(9) =103823a(10) =185193a(11) =226981a(12) =250047a(13) =389017a(14) =456533a(15) =704969a(16) =804357a(17) =2048383a(18) =2352637a(19) =3869893a(20) =5000211a(21) =5929741a(22) =9393931a(23) =11697083a(24) =13312053a(25) =13651919a(26) =14348907a(27) =15813251a(28) =19034163a(29) =20346417