Peculiar pattern found in ‘random’ prime numbers (http://www.nature.com/news/peculiar-pattern-found-in-random-prime-numbers-1.19550) Raw

prime-pattern.js

"use strict";

function primeSieve(max) {
  var sieve = [], primes = [];
  for (var i = 2; i <= max; ++i) {
    if (!sieve[i]) {
      primes.push(i);
      for (var j = i << 1; j <= max; j += i) {
        sieve[j] = true;
      }
    }
  }
  return primes;
}

function findDistribution(primes) {
  var distribution = {
    1: 0, 3: 0, 7: 0, 9: 0
  };

  for (var i = 3, l = primes.length - 1; i < l; ++i) {
    if (primes[i] % 10 == 1) {
      distribution[primes[i + 1] % 10]++;
    }
  }

  var sum = 0;
  for (var key in distribution) {
    sum += distribution[key];
  }

  for (var key in distribution) {
    distribution[key] = (distribution[key] / sum * 100).toFixed(4) + "%";
  }

  return distribution;
}

var primes = primeSieve(10000000);
var distribution = findDistribution(primes);

console.log(distribution);