Numbers k such that k and k^2 use only the digits 0, 5, 6, 7 and 8.

Terms

a(0) =0a(1) =76a(2) =760a(3) =766a(4) =7600a(5) =7660a(6) =7666a(7) =76000a(8) =76076a(9) =76600a(10) =76660a(11) =76666a(12) =760000a(13) =760760a(14) =766000a(15) =766600a(16) =766660a(17) =766666a(18) =875076a(19) =7600000a(20) =7607600a(21) =7660000a(22) =7666000a(23) =7666600a(24) =7666660a(25) =7666666a(26) =7668576a(27) =8660766a(28) =8750760a(29) =76000000