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 A066873 #38 Dec 13 2020 05:18:40 %S A066873 0,0,1,5,13,42,108,236,586,1427,3340,7642,17519,39374,87102,190775, %T A066873 415523,901312,1947667,4197267 %N A066873 Number of amicable pairs where smaller term of the pair is less than 10^n. %H A066873 Sergei Chernykh, <a href="http://sech.me/ap/index.html">Amicable pairs list</a>. %H A066873 Shyam Sunder Gupta, <a href="http://www.shyamsundergupta.com/amicable.htm">Amicable Numbers</a>. %H A066873 J. O. M. Pedersen, <a href="http://amicable.homepage.dk/knwnap.htm">Known Amicable Pairs</a>. [Broken link; <a href="https://web.archive.org/web/20131212143320/http://amicable.homepage.dk/knwnc2.htm">WayBackMachine archive</a>.] %H A066873 J. O. M. Pedersen, <a href="http://amicable.homepage.dk/tables.htm">Tables of Aliquot Cycles</a>. [Broken link; <a href="https://web.archive.org/web/20140502102524/http://amicable.homepage.dk:80/tables.htm">WayBackMachine archive</a>.] %H A066873 J. O. M. Pedersen, <a href="/A063990/a063990.pdf">Tables of Aliquot Cycles</a> [Cached copy, pdf file only] %H A066873 <a href="/index/Am#amicable">Index entries for sequences related to amicable numbers</a> %e A066873 There are 13 pairs with smaller term of the pair < 10^5, so a(5) = 13. %Y A066873 Cf. A063990, A259180 (amicable pairs). %K A066873 nonn,more %O A066873 1,4 %A A066873 _Shyam Sunder Gupta_, Jan 21 2002 %E A066873 Edited by _Klaus Brockhaus_, May 31 2003 %E A066873 a(15)-a(18) (from Sergei Chernykh's site) added by _Amiram Eldar_, Aug 19 2017 %E A066873 a(19) (from Sergei Chernykh's site) added by _Amiram Eldar_, Apr 05 2019 %E A066873 a(20) (from Sergei Chernykh's site) added by _Amiram Eldar_, Dec 13 2020