**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.

Assign the first two digits of Fibonacci sequence to 1 and 2 respectively and keep on generating new Fibonacci number by adding previous two. Check if the new Fibonacci number exceeds 4 million, if it does sum only the even valued numbers.

len <- 50 fibvals <- numeric(len) fibvals[1] <- 1 fibvals[2] <- 2 for (i in 3:len) { fibvals[i] <- fibvals[i-1]+fibvals[i-2] if(fibvals[i] > 4000000) { print(sum(fibvals[fibvals %% 2 == 0 ])) break } } # [1] 4613732

PS – the code on Github uses a different approach but gives the same answer.

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