Numbers k such that k and k^2 use only the digits 0, 4, 6, 7 and 8.

Terms

a(0) =0a(1) =8a(2) =78a(3) =80a(4) =88a(5) =780a(6) =800a(7) =878a(8) =880a(9) =7800a(10) =8000a(11) =8780a(12) =8800a(13) =8874a(14) =68474a(15) =78000a(16) =80000a(17) =80474a(18) =80478a(19) =86478a(20) =87800a(21) =88000a(22) =88740a(23) =88808a(24) =684740a(25) =778874a(26) =780000a(27) =800000a(28) =804740a(29) =804780