Numbers k such that k and k^2 use only the digits 0, 4, 5, 6 and 8.

Terms

a(0) =0a(1) =8a(2) =80a(3) =800a(4) =8000a(5) =80000a(6) =80408a(7) =800000a(8) =804080a(9) =6844008a(10) =8000000a(11) =8040800a(12) =8066008a(13) =68440080a(14) =80000000a(15) =80408000a(16) =80650508a(17) =80660080a(18) =684400800a(19) =800000000a(20) =804080000a(21) =806505080a(22) =806600800a(23) =6844008000a(24) =8000000000a(25) =8040800000a(26) =8065050800a(27) =8066008000a(28) =68440080000a(29) =80000000000