Numbers k such that k and k^2 use only the digits 0, 2, 5 and 8.

Terms

a(0) =0a(1) =5a(2) =50a(3) =500a(4) =505a(5) =2255a(6) =5000a(7) =5005a(8) =5050a(9) =22550a(10) =50000a(11) =50005a(12) =50050a(13) =50500a(14) =50555a(15) =225500a(16) =225505a(17) =500000a(18) =500005a(19) =500050a(20) =500500a(21) =500505a(22) =505000a(23) =505550a(24) =505555a(25) =508805a(26) =2255000a(27) =2255050a(28) =5000000a(29) =5000005