A161219 (1/n) * Sum_{d|n} phi(n/d)*2^(d+1).

4, 6, 8, 12, 16, 28, 40, 72, 120, 216, 376, 704, 1264, 2364, 4384, 8232, 15424, 29204, 55192, 104976, 199760, 381492, 729448, 1398504, 2684368, 5162856, 9942136, 19175160, 37025584, 71585136, 138547336, 268439592, 520602352, 1010588256, 1963413664, 3817763800