Numbers k such that k and k^2 use only the digits 1, 2, 3, 5 and 7.

Terms

a(0) =1a(1) =5a(2) =11a(3) =15a(4) =35a(5) =111a(6) =115a(7) =235a(8) =335a(9) =715a(10) =1235a(11) =2715a(12) =3335a(13) =3511a(14) =3515a(15) =3711a(16) =12335a(17) =27115a(18) =33335a(19) =33515a(20) =35711a(21) =37115a(22) =72335a(23) =75711a(24) =111235a(25) =123335a(26) =132335a(27) =177515a(28) =333335a(29) =333515