Numbers k such that k and k^2 use only the digits 1, 4, 5, 6 and 8.

Terms

a(0) =1a(1) =4a(2) =8a(3) =41a(4) =81a(5) =816a(6) =6441a(7) =6454a(8) =11881a(9) =64466a(10) =64546a(11) =641441a(12) =644581a(13) =684581a(14) =6454581a(15) =8114466a(16) =11881141a(17) =64541141a(18) =64661881a(19) =66448884a(20) =68444641a(21) =81556184a(22) =644658684a(23) =644861881a(24) =644868641a(25) =646618641a(26) =664414454a(27) =664564184a(28) =681585546a(29) =811488858