Numbers that occur as the number of primitive roots.
0, 1, 2, 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44, 48, 52, 54, 60, 64, 72, 80, 82, 84, 88, 92, 96, 100, 108, 112, 120, 128, 130, 132, 144, 156, 160, 162, 164, 168, 172, 176, 178, 180, 190, 192, 200, 204, 212, 216, 220, 232, 238, 240, 250, 252
1
T. D. Noe, Plot of 500 terms
T. D. Noe, Table of 500 terms
Eric W. Weisstein, MathWorld: Primitive Root
(Mma) nn = 10000; t = Join[{1}, Table[pr = PrimitiveRootList[n]; Length[pr], {n, 2, nn}]]; Take[Union[t], nn/100]
nonn
T. D. Noe, Mar 25 2015