A104019 Years in the Gregorian calendar for which Easter falls on the 25th day of the month.
1663, 1666, 1674, 1731, 1734, 1742, 1883, 1886, 1894, 1943, 1951, 2035, 2038, 2046, 2103, 2187, 2190, 2198, 2255, 2258, 2266, 2323, 2326, 2334, 2407, 2410, 2418, 2491, 2559, 2570, 2573, 2581, 2627, 2630, 2638, 2779, 2782, 2790, 2874, 2877, 2885, 2931
Offset: 1
Keywords
Links
- Holger Oertel, Calculation of Easter. [Via Wayback Machine]
- M. Montes, Frequency of the Date of Easter over one complete Gregorian Easter Cycle.
- Index entries for sequences related to calendars
Crossrefs
Cf. A104034.
Programs
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Mathematica
(* first do *) Needs["Miscellaneous`Calendar`"] (* then *) Select[ Range[1582, 2941], EasterSunday[ # ][[3]] == 25 &] (* Robert G. Wilson v, Apr 06 2005 *)
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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++; \ print(ct" "dt" "y-y2); print1(y","); if(y2<>y,y2=y); ); ); \ print1(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); }
Formula
The formula is based on the algorithm of Oudin (1940) taken from the link.
Extensions
More terms from Robert G. Wilson v, Apr 06 2005
Comments