A300065 Numbers k such that the number of residues modulo k of the maximum order is different from phi(phi(k)).

8, 12, 21, 24, 28, 33, 36, 42, 44, 56, 57, 63, 65, 66, 69, 72, 76, 77, 80, 84, 88, 91, 92, 93, 99, 108, 114, 117, 124, 126, 129, 130, 132, 133, 138, 141, 145, 147, 152, 154, 161, 168, 171, 172, 177, 182, 184, 185, 186, 188, 189, 195, 196, 198, 201, 207, 208, 209, 213, 216, 217, 228, 231, 234, 236, 237, 240, 248, 249, 252, 253, 258, 260, 264, 265, 266, 268, 273, 275, 276, 279, 282

Offset

1,1

Comments

Numbers k such that A111725(k) is not equal to A010554(k).

The ratio a(n)/n tends to 1 as n grows.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Peter J. Cameron and D. A. Preece, Primitive lambda-roots, 2014.

T. W. Müller and J.-C. Schlage-Puchta, On the number of primitive lambda-roots, Acta Arithmetica, Vol. 115 (2004), pp. 217-223.

Mathematica

q[n_] := Count[(t = Table[MultiplicativeOrder[k, n], {k, Select[Range[n], CoprimeQ[n, #] &]}]), Max[t]] != EulerPhi[EulerPhi[n]]; Select[Range[300], q] (* Amiram Eldar, Oct 12 2021 *)

Crossrefs

Complement of A300064.

Union of {8} and set difference of A024619 and A300080.

Cf. A000010, A002322, A010554, A111725, A300079.

Sequence in context: A072843 A354069 A350615 * A072902 A269705 A189322

Adjacent sequences: A300062 A300063 A300064 * A300066 A300067 A300068

Keyword

nonn

Author

Max Alekseyev, Feb 23 2018

Status

approved