Project Euler Problem 2

Project Euler R

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.

相変わらず解ければいいというスタンスで．

a <- c(1,2)
while (a[length(a)] < 4000000){
  a <- c(a,a[length(a)]+a[length(a)-1])
}
a <- a[1:length(a)-1]
sum(a[!a%%2])
4613732