Numbers k such that k and k^2 use only the digits 1, 4, 5, 8 and 9.

Terms

a(0) =1a(1) =9a(2) =141a(3) =441a(4) =941a(5) =1191a(6) =99559a(7) =118988a(8) =445488a(9) =999559a(10) =9958988a(11) =44544191a(12) =445919891a(13) =941195441a(14) =994458891a(15) =9195411891a(16) =9459859859a(17) =9994941191a(18) =11898949191a(19) =44551594191a(20) =44555449891a(21) =94858548141a(22) =99498181488a(23) =445145914891a(24) =445584958891a(25) =919184195441a(26) =945944814191