def problem25():
"""
The Fibonacci sequence is defined by the recurrence relation:
F_(n) = F_(n-1) + F_(n-2), where F_(1) = 1 and F_(2) = 1.
What is the first term in the Fibonacci sequence to contain 1000 digits?
F1 = 1
F2 = 1
F3 = 2
"""
generator = mlib.fib()
count = 1
while True:
n = generator.next()
count += 1
if len(str(n)) == 1000:
return count
def problem2():
"""
Each new term in the Fibonacci sequence is generated by adding
the previous two terms. By starting with 1 and 2, the first 10 terms will be:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
Find the sum of all the even-valued terms in the sequence which
do not exceed four million.
"""
sum = 0
generator = mlib.fib()
while True:
f = generator.next()
if f > 4000000:
break
if f%2 == 0:
sum += f
return sum
