Numbers k such that k and k^2 use only the digits 1, 2, 5, 6 and 8.

Terms

a(0) =1a(1) =5a(2) =11a(3) =15a(4) =16a(5) =25a(6) =81a(7) =125a(8) =261a(9) =285a(10) =511a(11) =515a(12) =516a(13) =816a(14) =1125a(15) =1285a(16) =1585a(17) =2261a(18) =2285a(19) =2581a(20) =2585a(21) =5125a(22) =11211a(23) =12511a(24) =12515a(25) =12581a(26) =25525a(27) =25615a(28) =26125a(29) =28615