Numbers whose base-10 representation has the same nonzero number of 0's and 2's.

Terms

a(0) =20a(1) =102a(2) =120a(3) =201a(4) =203a(5) =204a(6) =205a(7) =206a(8) =207a(9) =208a(10) =209a(11) =210a(12) =230a(13) =240a(14) =250a(15) =260a(16) =270a(17) =280a(18) =290a(19) =302a(20) =320a(21) =402a(22) =420a(23) =502a(24) =520a(25) =602a(26) =620a(27) =702a(28) =720a(29) =802