def run():
sum = 0
for i in range(10001):
if eu.is_square(i):
continue
cf = eu.sqrt_continued_fraction(i)
if len(cf) % 2 == 0:
sum += 1
return sum
def test():
sum = 0
for i in range(14):
if eu.is_square(i):
continue
cf = sqrt_continued_fraction(i)
if len(cf) % 2 == 0:
sum += 1
assert sum == 4, 'there are only 4 matches for x <=13'
def max_x(max_d):
'''
for all d <= max_d, this finds the d for which the
solution to Pell (x,y) minimizing x is maximal in x.
'''
max = 0
rslt = None
for d in range(2,max_d + 1):
if eu.is_square(d):
continue
x,y = pell_min_x(d)
if x > max:
max = x
rslt = d
return rslt
