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Problem 2


Problem 2


Even Fibonacci numbers

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:

$$1, 2, 3, 5, 8, 13, 21, 34, 55, 89, \ldots$$

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.


偶斐波那契数

斐波那契数列中的每一项都是前两项的和。由$1$和$2$开始生成的斐波那契数列的前$10$项为:

$$1, 2, 3, 5, 8, 13, 21, 34, 55, 89, \ldots$$

考虑该斐波那契数列中不超过四百万的项,求其中为偶数的项之和。