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 A183078 #9 Feb 18 2019 06:10:50 %S A183078 8796093022207,604462909807314587353087, %T A183078 12554203470773361527671578846415332832204710888928069025791, %U A183078 4171849679533027504677776769862406473833407270227837441302815640277772901915313574263597826047 %N A183078 Composite numbers of the form 2^p - 1, with p prime, for which each prime divisor has the form 4j + 3. %C A183078 Needed factorizations are in the Cunningham Project. %H A183078 Amiram Eldar, <a href="/A183078/b183078.txt">Table of n, a(n) for n = 1..12</a> %H A183078 S. S. Wagstaff, Jr., <a href="http://homes.cerias.purdue.edu/~ssw/cun/index.html">The Cunningham Project</a>. %F A183078 a(n) = 2^A183074(n) - 1. %e A183078 8796093022207 = 2^43 - 1 = 431 * 9719 * 2099863. %Y A183078 Cf. A000668, A136005, A183075, A183076, A183077. %Y A183078 Cf. A000043, A136003, A183071, A183072, A183073, A183074. %K A183078 nonn,hard %O A183078 1,1 %A A183078 _Stuart Clary_, Dec 23 2010