A049355 Digitally balanced numbers in base 4: equal numbers of 0's, 1's, ... 3's.

75, 78, 99, 108, 114, 120, 135, 141, 147, 156, 177, 180, 198, 201, 210, 216, 225, 228, 16815, 16827, 16830, 16875, 16878, 16890, 17007, 17019, 17022, 17055, 17079, 17085, 17115, 17118, 17127, 17133, 17142, 17145, 17259, 17262, 17274