A039472 Numbers n such that representation in base 11 has same nonzero number of 4's and 5's.

49, 59, 170, 180, 291, 301, 412, 422, 489, 500, 511, 522, 539, 540, 541, 542, 545, 546, 547, 548, 549, 555, 566, 577, 588, 599, 609, 620, 631, 642, 649, 650, 651, 652, 655, 656, 657, 658, 659, 675, 686, 697, 708, 719, 775, 785, 896, 906, 1017, 1027