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A104034 Years between occurrences of Easter on the 25th of the month in the Gregorian calendar.

%I A104034 #20 Aug 15 2020 08:48:00
%S A104034 3,8,57,3,8,141,3,8,49,8,84,3,8,57,84,3,8,57,3,8,57,3,8,73,3,8,73,68,
%T A104034 11,3,8,46,3,8,141,3,8,84,3,8,46,11,3,8,49,8,73,11,3,54,3,8,84,3,8,46,
%U A104034 3,8,84,68,3,8,46,11,3,8,73,3,8,141,11,3,8,46,3,8,57,84,3,8,84,3,8,46,11
%N A104034 Years between occurrences of Easter on the 25th of the month in the Gregorian calendar.
%C A104034 Easter was celebrated on the 25th in 1742. It was not celebrated on the 25th again until 1883, 141 years later.
%H A104034 Holger Oertel, <a href="https://web.archive.org/web/20120314005924/http://www.ortelius.de/kalender/east_en.php">Calculation of Easter</a>. [Via Wayback Machine]
%H A104034 <a href="/index/Ca#calendar">Index entries for sequences related to calendars</a>
%F A104034 The formula is based on the algorithm of Oudin (1940) taken from the link.
%o A104034 (PARI) edate(yr1,yr2,day) = { local(flag=1,d,y,y2,ct,dt); for(d=day,day, ct=0; for(y=yr1,yr2, dt=oudin(y); if(eval(mid(dt,4,2))==d, if(flag,y2=y;flag=0); ct++; print1(y-y2","); if(y2<>y,y2=y); ); ); \ print(d","ct); ) } oudin(y) = \This is based on the algorithm of Oudin (1940) { local(c,n,k,i1,i2,i3,a1,a2,m,d,l,dt,dat=""); c=floor(y/100); n=y-19*floor(y/19); k=floor((c-17)/25); i1=c-floor(c/4)-floor((c-k)/3)+19*n+15; i2=i1-30*floor(i1/30); i3=i2-floor(i2/28)*(1-floor(i2/28)*floor(29/(i2+1))*floor((21-n)/11)); a1=y+floor(y/4)+i3+2-c+floor(c/4); a2=a1-7*floor(a1/7); l=i3-a2; m=3+floor((l+40)/44); d=l+28-31*floor(m/4); dat = concat(dat,right(Str(m+100),2)); dat = concat(dat," "); dat = concat(dat,right(Str(d+100),2)); dat = concat(dat," "); dat = concat(dat,Str(y)); return(dat); }
%K A104034 nonn
%O A104034 1583,1
%A A104034 _Cino Hilliard_, Mar 31 2005