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 A007802 #37 Apr 22 2015 16:04:57 %S A007802 3,5,17,31,127,257,511,683,2047,2731,3277,3641,8191,43691,52429,61681, %T A007802 65537,85489,131071,174763,178481,233017,253241,256999,486737,524287, %U A007802 704093,838861,1016801,1082401,1657009,1838599,1965379,2304167,2796203,3033169,3303821 %N A007802 Numbers n such that game of n X n Button Madness need have no solution; this lists only the primitive elements of the set. %C A007802 Primitive elements of A165740. - _Thomas Buchholz_, May 23 2014 %C A007802 _Andries E. Brouwer_ remarks that it can be shown that this sequence is infinite and contains A000668 > 7 and A019434. - _Thomas Buchholz_, May 23 2014 %H A007802 N. J. A. Sloane, <a href="/A007802/b007802.txt">Table of n, a(n) for n = 1..42</a> [Copied from Brouwer's MAD numbers web page] %H A007802 Andries E. Brouwer, <a href="http://www.win.tue.nl/~aeb/ca/madness/mad.html">MAD numbers</a> %Y A007802 Cf. A000668, A019434, A165740. %K A007802 nonn %O A007802 1,1 %A A007802 Aart Blokhuis (aartb(AT)win.tue.nl), Mar 15 1996 %E A007802 More terms from _Andries E. Brouwer_, May 31 2002, Sep 10 2012