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 A081245 #9 Feb 25 2021 21:28:01 %S A081245 20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,5,20,20,20,20, %T A081245 20,20,20,20,20,20,20,20,20,20,20,20,20,20,5,20,20,20,20,20,20,20,20, %U A081245 20,20,20,20,20,20,20,20,20,20,5 %N A081245 Number of days in months in the Haab year of Mayan/Mesoamerican calendars. %H A081245 C. Tondering, <a href="http://www.tondering.dk/claus/calendar.html">The Calendar FAQ</a> %H A081245 <a href="/index/Ca#calendar">Index entries for sequences related to calendars</a> %F A081245 G.f. 20/(1-x)-15*x^19/(1-x^19). %Y A081245 Cf. A081244. %K A081245 nonn %O A081245 1,1 %A A081245 _Ralf Stephan_, Mar 12 2003