Numbers k such that k and k^2 use only the digits 1, 2, 4, 6 and 8.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =11a(5) =12a(6) =21a(7) =22a(8) =41a(9) =46a(10) =68a(11) =121a(12) =122a(13) =162a(14) =168a(15) =221a(16) =261a(17) =262a(18) =642a(19) =668a(20) =1488a(21) =4262a(22) =6441a(23) =6642a(24) =6668a(25) =8162a(26) =8261a(27) =11141a(28) =11142a(29) =14881