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%I #19 Jun 14 2022 02:28:32
%S 6,12,24,30,48,66,78,96,102,114,132,138,150,174,186,192,204,222,228,
%T 246,258,264,276,282,318,348,354,366,372,384,390,402,426,438,444,456,
%U 474,492,498,510,516,528,534,552,564,570,582,606,618,636,642,654,678
%N Numbers k such that gcd(k, 2^k-1) = 3.
%C The number of terms not exceeding 10^m, for m = 1, 2, ..., are 1, 8, 79, 793, 7935, 79349, 793524, 7935094, 79350930, 793509394, ... . Apparently, the asymptotic density of this sequence exists and equals 0.0793509... . - _Amiram Eldar_, Jun 14 2022
%H Amiram Eldar, <a href="/A069171/b069171.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[700],GCD[#,2^#-1]==3&] (* _Harvey P. Dale_, Nov 22 2011 *)
%t Select[Range[700], GCD[#, PowerMod[2, #, #] - 1] == 3 &] (* _Amiram Eldar_, Jun 14 2022 *)
%Y Cf. A014491.
%K easy,nonn
%O 1,1
%A _Benoit Cloitre_, Apr 09 2002
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