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

Terms

a(0) =0a(1) =5a(2) =50a(3) =500a(4) =505a(5) =5000a(6) =5005a(7) =5050a(8) =50000a(9) =50005a(10) =50050a(11) =50500a(12) =500000a(13) =500005a(14) =500050a(15) =500500a(16) =500505a(17) =505000a(18) =5000000a(19) =5000005a(20) =5000050a(21) =5000500a(22) =5000505a(23) =5005000a(24) =5005050a(25) =5050000a(26) =5050005a(27) =50000000a(28) =50000005a(29) =50000050