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 A183077 #9 Feb 18 2019 06:05:17 %S A183077 3,7,31,127,8191,131071,524287,2147483647,8796093022207, %T A183077 2305843009213693951,604462909807314587353087, %U A183077 618970019642690137449562111,162259276829213363391578010288127,170141183460469231731687303715884105727 %N A183077 Numbers of the form 2^p - 1, with p prime, for which each prime divisor has the form 4j + 3. %C A183077 The Mersenne primes (A000668) are contained in this sequence. %C A183077 Needed factorizations are in the Cunningham Project. %H A183077 Amiram Eldar, <a href="/A183077/b183077.txt">Table of n, a(n) for n = 1..26</a> %H A183077 S. S. Wagstaff, Jr., <a href="http://homes.cerias.purdue.edu/~ssw/cun/index.html">The Cunningham Project</a>. %F A183077 a(n) = 2^A183073(n) - 1. %e A183077 8796093022207 = 2^43 - 1 = 431 * 9719 * 2099863. %Y A183077 Cf. A000668, A136005, A183075, A183076, A183078. %Y A183077 Cf. A000043, A136003, A183071, A183072, A183073, A183074. %K A183077 nonn,hard %O A183077 1,1 %A A183077 _Stuart Clary_, Dec 23 2010