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 A268174 #8 Mar 18 2016 12:58:52 %S A268174 1,3,5,9,11,15,17,21,27,29,35,39,41,45,51,57,59,65,69,71,77,81,87,95, %T A268174 99,101,105,107,111,125,129,135,137,147,149,155,161,165,171,177,179, %U A268174 189,191,195,197,209,221,225,227,231,237,239,249,255,261,267,269,275,279,281,291,305,309,311,315,329,335,339,345 %N A268174 Integers m such that m^(m+1) == 1 (modulo (m+2)). %C A268174 Integers m such that A110146(m)=1. %C A268174 Note that in many cases these terms are also in A040976 (primes minus 2). %C A268174 First terms that are not in A040976 are: 339, 559, 643, 1103, 1385, 1727, 1903, 2045, 2463, 2699, 2819. What is the pattern of these numbers? %H A268174 Harvey P. Dale, <a href="/A268174/b268174.txt">Table of n, a(n) for n = 1..1000</a> %t A268174 Select[Range[400],PowerMod[#,#+1,#+2]==1&] (* _Harvey P. Dale_, Mar 18 2016 *) %Y A268174 Cf. A110146, A040976 (prime(n) - 2). %K A268174 nonn %O A268174 1,2 %A A268174 _Zak Seidov_, Jan 28 2016