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 A068535 #18 Jun 19 2022 02:21:43 %S A068535 1,2,4,8,16,32,35,64,128,256,297,512,1024,1093,2048,2186,2590,3279, %T A068535 3511,4096,4372,5465,6558,7022,7651,8192,8744,9837,10533,10930,13116, %U A068535 14044,14209,16384,21066,23175,24012,24577,26592,28088,31599,32768,35110,38621,42132 %N A068535 Numbers k such that 2^k mod k = 2^k mod k^2. %C A068535 Sequence contains all numbers of the form 2^k (A000079) but also many others as the subsequence of primes in A001220. %H A068535 Amiram Eldar, <a href="/A068535/b068535.txt">Table of n, a(n) for n = 1..72</a> %t A068535 Select[Range[33000],PowerMod[2,#,#]==PowerMod[2,#,#^2]&] (* _Harvey P. Dale_, Oct 29 2017 *) %Y A068535 Cf. A000079, A001220, A125773, A125774, A125775. %K A068535 easy,nonn %O A068535 1,2 %A A068535 _Benoit Cloitre_, Mar 22 2002 %E A068535 More terms from _Amiram Eldar_, Jun 19 2022