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%I #19 Oct 23 2021 10:06:20
%S 1,3,9,27,39,81,117,171,243,351,507,513,729,1053,1521,1539,2187,2223,
%T 3081,3159,3249,4563,4617,5109,6123,6561,6591,6669,9243,9477,9747,
%U 13689,13851,15327,18153,18369,19683,19773,20007,27729,28431,28899,29241,39159,40053
%N Numbers k that divide 7^k + 2^k.
%H Amiram Eldar, <a href="/A045580/b045580.txt">Table of n, a(n) for n = 1..2000</a>
%t Select[Range[30000], Divisible[PowerMod[2, #, #] + PowerMod[7, #, #], #] &] (* _Amiram Eldar_, Oct 23 2021 *)
%Y Cf. A074602.
%K nonn
%O 1,2
%A _David W. Wilson_