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 A184269 #20 Jan 20 2018 16:14:49 %S A184269 20,1182,99880,9587580,981706832,104715443852,11488774559744, %T A184269 1286742755471400,146402730743793240,16865594582168158776, %U A184269 1962541914958813595480,230271584688553159320640,27207473390887478569212080,3233802551602631768613571584 %N A184269 Number of distinct n X 7 toroidal binary arrays. %H A184269 Vaclav Kotesovec, <a href="/A184269/b184269.txt">Table of n, a(n) for n = 1..470</a> %H A184269 S. N. Ethier, <a href="http://arxiv.org/abs/1301.2352">Counting toroidal binary arrays</a>, arXiv preprint arXiv:1301.2352, 2013 and <a href="https://cs.uwaterloo.ca/journals/JIS/VOL16/Ethier/ethier2.html">J. Int. Seq. 16 (2013) #13.4.7</a>. %F A184269 a(n) ~ 128^n / (7*n). - _Vaclav Kotesovec_, Sep 04 2014 %p A184269 with(numtheory): %p A184269 a:= n-> add(add(phi(c)*phi(d) *2^(7*n/ilcm(c, d)), %p A184269 d=divisors(n)), c=[1,7])/(7*n): %p A184269 seq(a(n), n=1..20); # _Alois P. Heinz_, Aug 25 2012 %Y A184269 Column 7 of A184271. %K A184269 nonn %O A184269 1,1 %A A184269 _R. H. Hardin_, Jan 10 2011 %E A184269 More terms from _Alois P. Heinz_, Aug 25 2012