Numbers whose base-10 representation has the same nonzero number of 2's and 5's.

Terms

a(0) =25a(1) =52a(2) =125a(3) =152a(4) =205a(5) =215a(6) =235a(7) =245a(8) =250a(9) =251a(10) =253a(11) =254a(12) =256a(13) =257a(14) =258a(15) =259a(16) =265a(17) =275a(18) =285a(19) =295a(20) =325a(21) =352a(22) =425a(23) =452a(24) =502a(25) =512a(26) =520a(27) =521a(28) =523a(29) =524