import itertools
from fractions import Fraction

def series(u0=Fraction(3, 2), u1=Fraction(5, 3)):
    yield u0
    yield u1
    while u0 != u1:
        un = 2003 - 6002/u1 + 4000/(u1*u0)
        yield un
        u1, u0 = un, u1

for i, u in enumerate(itertools.islice(series(), 100)):
    err = (2-u)/2 # relative error
    print("%d\t%.2g" % (i, err))