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A197930 Numbers n such that the number of distinct residues in x^(n-1) (mod n), x=0..n-1, equals n. 4
1, 2, 6, 10, 14, 22, 26, 30, 34, 38, 42, 46, 58, 62, 74, 78, 82, 86, 94, 102, 106, 110, 114, 118, 122, 134, 138, 142, 146, 158, 166, 170, 174, 178, 182, 194, 202, 206, 210, 214, 218, 222, 226, 230, 254, 258, 262, 266, 274, 278, 282, 290, 298, 302, 314, 318 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = n if n = 2p,  p prime > 2, or n = 2q with q nonprime such that q = 1, 15, 21, 39, 51, 55, 57, 69, 85, 87, 91,…

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

n such that A197929(n) = n.

EXAMPLE

a(8) = 30 because x^29  == 0,1,2, …,28,29  (mod 30) with 30 distinct residues.

MATHEMATICA

lst={}; Table[If[Length[Union[PowerMod[Range[0, n-1], n-1, n]]]==n, AppendTo[lst, n]], {n, 320}]; lst

Select[Range[400], Length[Union[PowerMod[Range[0, #-1], #-1, #]]]==#&] (* Harvey P. Dale, Nov 06 2016 *)

CROSSREFS

Cf. A197929, A195637.

Sequence in context: A185548 A239221 A039956 * A192109 A216090 A118369

Adjacent sequences:  A197927 A197928 A197929 * A197931 A197932 A197933

KEYWORD

nonn

AUTHOR

Michel Lagneau, Oct 19 2011

STATUS

approved

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Last modified July 12 18:03 EDT 2020. Contains 335666 sequences. (Running on oeis4.)