A277626 - OEIS

A277626

Odd numbers n such that 2^n == phi(n) (mod n).

1, 3, 15, 255, 65535, 4139059, 15734689, 66322477, 83623935, 4294967295

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

MATHEMATICA

Join[{1}, Select[Range[1, 4140001, 2], PowerMod[2, #, #]==EulerPhi[#]&]] (* The program generates the first 6 terms of the sequence. *) (* Harvey P. Dale, Feb 07 2025 *)

PROG

(PARI) is(n)=Mod(2, n)^n==eulerphi(n)&&n%2==1;

CROSSREFS

Cf. A000010, A000079, A015910.

Sequence in context: A139289 A116518 A247174 * A050474 A250405 A051179

Adjacent sequences: A277623 A277624 A277625 * A277627 A277628 A277629

KEYWORD

nonn,more

AUTHOR

Altug Alkan, Dec 11 2016

STATUS

approved