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A069049

Numbers k such that 2^k mod k = 2^phi(k) mod phi(k).

1, 2, 4, 8, 14, 16, 22, 26, 32, 44, 46, 52, 62, 64, 92, 94, 108, 112, 118, 124, 128, 154, 164, 166, 188, 214, 222, 234, 236, 244, 252, 256, 258, 264, 288, 332, 334, 336, 358, 390, 412, 428, 438, 454, 456, 504, 512, 526, 534, 546, 576, 582, 630, 664, 668, 672

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Numbers k such that A015910(k) = A015910(A000010(k)). - Michel Marcus, Feb 11 2021

LINKS

Table of n, a(n) for n=1..56.

MATHEMATICA

Select[Range[1000], PowerMod[2, #, #] == PowerMod[2, (e = EulerPhi[#]), e] &] (* Amiram Eldar, Feb 11 2021 *)

PROG

(PARI) f(n) = lift(Mod(2, n)^n); \\ A015910

isok(k) = f(k) == f(eulerphi(k)); \\ Michel Marcus, Feb 11 2021