Even Fibonacci numbers
Problem 2
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, ...
By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
def run(limit=4000000):
a = 1
b = 1
result = 0
while result < limit:
result += (a + b)
a, b = a + 2 * b, 2 * a + 3 * b
return result