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A104019 Years in the Gregorian calendar for which Easter falls on the 25th day of the month. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The starting point for the sequence is explained by the fact that the Gregorian calendar was only introduced in 1582.
The complete Easter cycle lasts 5700000 years. In this cycle, Mar 25 occurs 110200 times and Apr 25 occurs 42000 times for a total of 152200 times. This reduces to 761 occurrences every 28500 years (~2.67%). - Hans Havermann, Jan 27 2008
LINKS
Holger Oertel, Calculation of Easter. [Via Wayback Machine]
FORMULA
The formula is based on the algorithm of Oudin (1940) taken from the link.
MATHEMATICA
(* first do *) Needs["Miscellaneous`Calendar`"] (* then *) Select[ Range[1582, 2941], EasterSunday[ # ][[3]] == 25 &] (* Robert G. Wilson v, Apr 06 2005 *)
PROG
(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); }
CROSSREFS
Cf. A104034.
Sequence in context: A236042 A163273 A340923 * A054810 A251888 A251785
KEYWORD
nonn
AUTHOR
Cino Hilliard, Mar 31 2005
EXTENSIONS
More terms from Robert G. Wilson v, Apr 06 2005
STATUS
approved

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Last modified April 18 13:10 EDT 2024. Contains 371780 sequences. (Running on oeis4.)