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 A081244 #12 Feb 25 2021 21:27:50 %S A081244 1,20,260,360,365,7200,18980,144000,2880000,57600000,1152000000, %T A081244 23040000000 %N A081244 Named periods in the Mayan/Mesoamerican calendars. %C A081244 The periods are named kin, winal, Tzolkin year, tun, Haab year, katun, Calendar Round, baktun, pictun, calabtun, kinchiltun, alautun. With approximately 63 million years, the alautun is probably the longest named period in any calendar. %H A081244 C. Tondering, <a href="http://www.tondering.dk/claus/calendar.html">The Calendar FAQ</a> %H A081244 <a href="/index/Ca#calendar">Index entries for sequences related to calendars</a> %Y A081244 Cf. A081245, A115100. %K A081244 nonn,fini,full %O A081244 0,2 %A A081244 _Ralf Stephan_, Mar 12 2003