A007998 Number of primitive solutions to x+y+z=0 (mod n).

1, 2, 3, 3, 4, 5, 5, 7, 8, 9, 9, 15, 11, 17, 17, 18, 18, 31, 21, 33, 30, 33, 30, 53, 34, 48, 46, 53, 43, 87, 47, 73, 69, 79, 66, 110, 65, 100, 94, 111, 80, 159, 86, 135, 130, 135, 108, 202, 116, 181, 153, 175, 133, 255, 150, 212