Numbers k such that k and k^2 use only the digits 2, 3, 5, 7 and 8.

Terms

a(0) =5a(1) =85a(2) =235a(3) =885a(4) =2885a(5) =7585a(6) =22885a(7) =27885a(8) =72335a(9) =73385a(10) =75885a(11) =87885a(12) =287885a(13) =522335a(14) =572585a(15) =723385a(16) =723585a(17) =733385a(18) =852835a(19) =2352835a(20) =2752885a(21) =2885885a(22) =5222335a(23) =5222885a(24) =5223335a(25) =5232385a(26) =5327835a(27) =5772585a(28) =5777835a(29) =7272385