This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A069171 #19 Jun 14 2022 02:28:32 %S A069171 6,12,24,30,48,66,78,96,102,114,132,138,150,174,186,192,204,222,228, %T A069171 246,258,264,276,282,318,348,354,366,372,384,390,402,426,438,444,456, %U A069171 474,492,498,510,516,528,534,552,564,570,582,606,618,636,642,654,678 %N A069171 Numbers k such that gcd(k, 2^k-1) = 3. %C A069171 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 A069171 Amiram Eldar, <a href="/A069171/b069171.txt">Table of n, a(n) for n = 1..10000</a> %t A069171 Select[Range[700],GCD[#,2^#-1]==3&] (* _Harvey P. Dale_, Nov 22 2011 *) %t A069171 Select[Range[700], GCD[#, PowerMod[2, #, #] - 1] == 3 &] (* _Amiram Eldar_, Jun 14 2022 *) %Y A069171 Cf. A014491. %K A069171 easy,nonn %O A069171 1,1 %A A069171 _Benoit Cloitre_, Apr 09 2002