Harikrishnan Balagopal

Software Engineer at IBM Research,

IIT Kanpur Alumnus

Euler 2 - Even Fibonacci numbers

Euler 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.

const N = 4000000;
let sum = 0;
let a = 0;
let b = 1;
while (b < N) {
    if(b % 2 === 0) sum += b;
    const t = b;
    b = a + b;
    a = t;
}
console.log('sum', sum);