A300080 - OEIS

A300080

Numbers k that are not prime powers, and have exactly phi(phi(k)) residues modulo k of the maximum order.

6, 10, 14, 15, 18, 20, 22, 26, 30, 34, 35, 38, 39, 40, 45, 46, 48, 50, 51, 52, 54, 55, 58, 60, 62, 68, 70, 74, 75, 78, 82, 85, 86, 87, 90, 94, 95, 96, 98, 100, 102, 104, 105, 106, 110, 111, 112, 115, 116, 118, 119, 120, 122, 123, 134, 135, 136, 140, 142, 143, 144, 146, 148, 150, 153, 155, 156, 158, 159, 160, 162, 164, 165, 166

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OFFSET

1,1

COMMENTS

Numbers k with at least two distinct prime factors (A024619) such that A111725(k) = A010554(k).

LINKS

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

MATHEMATICA

q[n_] := Count[(t = Table[MultiplicativeOrder[k, n], {k, Select[Range[n], CoprimeQ[n, #] &]}]), Max[t]] == EulerPhi[EulerPhi[n]]; Select[Range[200], PrimeNu[#] > 1 && q[#] &] (* Amiram Eldar, Oct 12 2021 *)

CROSSREFS

Set difference of: A300064 and A000961, A300079 and A246547, A024619 and A300065.

Cf. A000010, A002322, A010554, A111725.

Sequence in context: A143907 A132982 A354922 * A069169 A230766 A231877

Adjacent sequences: A300077 A300078 A300079 * A300081 A300082 A300083

KEYWORD

nonn

AUTHOR

Max Alekseyev, Feb 24 2018

STATUS

approved