Numbers whose base-10 representation has the same nonzero number of 4's and 9's.

Terms

a(0) =49a(1) =94a(2) =149a(3) =194a(4) =249a(5) =294a(6) =349a(7) =394a(8) =409a(9) =419a(10) =429a(11) =439a(12) =459a(13) =469a(14) =479a(15) =489a(16) =490a(17) =491a(18) =492a(19) =493a(20) =495a(21) =496a(22) =497a(23) =498a(24) =549a(25) =594a(26) =649a(27) =694a(28) =749a(29) =794