OFFSET
1583,1
COMMENTS
Easter was celebrated on the 25th in 1742. It was not celebrated on the 25th again until 1883, 141 years later.
LINKS
Holger Oertel, Calculation of Easter. [Via Wayback Machine]
FORMULA
The formula is based on the algorithm of Oudin (1940) taken from the link.
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++; 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); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, Mar 31 2005
STATUS
approved