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Numbers k that divide 5^k + 2^k.
1

%I #20 Oct 23 2021 10:06:17

%S 1,7,49,343,2401,11179,16807,24059,78253,117649,168413,547771,823543,

%T 1178891,3834397,5764801,8252237,11812969,17852863,23649997,26840779,

%U 34591207,38422223,40353607,57765659,82690783,94527811,124970041,165549979,178539809,187885453

%N Numbers k that divide 5^k + 2^k.

%H Amiram Eldar, <a href="/A045578/b045578.txt">Table of n, a(n) for n = 1..64</a>

%t Select[Range[200000], Divisible[PowerMod[2, #, #] + PowerMod[5, #, #], #] &] (* _Amiram Eldar_, Oct 23 2021 *)

%Y Cf. A074600.

%K nonn

%O 1,2

%A _David W. Wilson_

%E More terms from _Amiram Eldar_, Oct 23 2021