A043452 Numbers n such that number of 7's in base 8 is 4.

4095, 8191, 12287, 16383, 20479, 24575, 28671, 29183, 29695, 30207, 30719, 31231, 31743, 32255, 32319, 32383, 32447, 32511, 32575, 32639, 32703, 32711, 32719, 32727, 32735, 32743, 32751, 32759, 32760, 32761, 32762