Based on the 14 step algorithm reported in "Calendar" by David Ewing Duncan (ISBN0-380-79324-5)
a=mod(year,19)
b=idiv(year,100)
c=mod(year,100)
d=idiv(b,4)
e=mod(b,4)
f=idiv((b+8),25)
g=idiv((b-f+1),3)
h=mod((19*a+b-d-g+15),30)
i=idiv(c,4)
k=mod(c,4)
l=mod((32+2*e+2*i-h-k),7)
m=idiv((a+11*h+22*l),451)
Easter_month=idiv((h+l-7*m+114),31)
p=mod((h+l-7*m+114),31)
Easter_day=p+1
Transcribed by Avi Meshar, 99-08-16
!
Easter_date=(mod((mod((19*mod(year,19)+idiv(year,100)-idiv(idiv(year,100),4)-idiv((idiv(year,100)-idiv((idiv(year,100)+8),25)+1),3)+15),30)+mod((32+2*mod(idiv(year,100),4)+2*idiv(mod(year,100),4)-mod((19*mod(year,19)+idiv(year,100)-idiv(idiv
(year,100),4)-idiv((idiv(year,100)-idiv((idiv (year,100)+8),25)+1),3)+15),30)-mod(mod(year, 100),4)),7) 7*idiv((mod(year,19)+11*mod((19*mod (year,19)+idiv(year,100)-idiv(idiv(year,100),4)-idiv((idiv(year,100)-idiv((idiv(year,100)+8),25) +1),3)+15),30)+22*mod((32+2*mod(idiv(year,100),4)+2*idiv(mod(year,100),4)-mod((19*mod(year,19)+ idiv(year,100)-idiv(idiv(year,100),4)-idiv((idiv (year,100)-idiv((idiv(year,100)+8),25)+1),3)+ 15),30)-mod(mod(year,100),4)),7)),451)+114), 31)+1)/100+(idiv((mod((19*mod(year,19)+idiv(year,100)-idiv(idiv(year,100),4)-idiv((idiv(year,100)-idiv((idiv(year,100)+8),25)+1),3)+15),30)+mod((32+2*mod(idiv(year,100),4)+2*idiv(mod(year,100),4)-mod((19*mod(year,19)+idiv(year,100)-idiv(idiv (year,100),4)-idiv((idiv(year,100)idiv((idiv (year,100)+8),25)+1),3)+15),30)-mod(mod(year, 100),4)),7)-7*idiv((mod(year,19)+11*mod((19*mod (year,19)+idiv(year,100)-idiv(idiv(year,100),4)-idiv((idiv(year,100)-idiv((idiv(year,100)+8),25) +1),3)+15),30)+22*mod((32+2*mod(idiv(year,100),4)+2*idiv(mod(year,100),4)-mod((19*mod(year,19) +idiv(year,100)-idiv(idiv(year,100),4)-idiv ((idiv(year,100)-idiv((idiv(year,100)+8),25)+1), 3)+15),30)mod(mod(year,100),4)),7)),451)+114),31))