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

Terms

a(0) =1a(1) =2a(2) =5a(3) =11a(4) =12a(5) =15a(6) =21a(7) =112a(8) =211a(9) =212a(10) =229a(11) =1515a(12) =4415a(13) =4421a(14) =95512a(15) =119229a(16) =119415a(17) =145415a(18) =221911a(19) =222511a(20) =222515a(21) =222521a(22) =442212a(23) =459521a(24) =491421a(25) =494211a(26) =494421a(27) =494511a(28) =499229a(29) =499521