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 A147984 #4 Jan 30 2017 21:26:09 %S A147984 1,2431,4061871,7528988476,15467641899285,34155922905682979, %T A147984 79397199549271412737,191739533381111401455478, %U A147984 476872353039366288373555323 %N A147984 Column 5 of A144512. %H A147984 Moa Apagodu, David Applegate, N. J. A. Sloane, and Doron Zeilberger, <a href="http://arxiv.org/abs/1701.08394">Analysis of the Gift Exchange Problem</a>, arXiv:1701.08394, 2017. %H A147984 David Applegate and N. J. A. Sloane, <a href="http://arxiv.org/abs/0907.0513">The Gift Exchange Problem</a> (arXiv:0907.0513, 2009) %Y A147984 Cf. A144512, A048775, A144511, A144662. %K A147984 nonn %O A147984 0,2 %A A147984 _N. J. A. Sloane_, May 13 2009