Numbers k such that k and k^2 use only the digits 1, 2, 3, 6 and 8.

Terms

a(0) =1a(1) =6a(2) =11a(3) =111a(4) =261a(5) =8131a(6) =36361a(7) =116881a(8) =162261a(9) =163361a(10) =183881a(11) =362131a(12) =1166881a(13) =1366881a(14) =1616361a(15) =1683111a(16) =2612131a(17) =3366361a(18) =3636361a(19) =6218381a(20) =11666881a(21) =16316361a(22) =28863881a(23) =28868361a(24) =36223361a(25) =112322131a(26) =116666881a(27) =116883131a(28) =162383131a(29) =168131861