Example #1
0
func mostConsecutivePrimeBelow(n int) int {

	sieve := utils.Sieve(n)
	count := 0

	// get all primes below n
	for _, i := range sieve {
		if !i {
			count++
		}
	}
	k, primes := 0, make([]int, count)
	for i, j := range sieve {
		if !j {
			primes[k] = i
			k++
		}
	}

	// find the prime expressible as the sum
	// of most number of consecutive primes
	prime, max := 0, 0
	for i := 0; i < count; i++ {
		for sum, j := primes[i], i; j+1 < count && sum < n; j++ {
			if !sieve[sum] && j+1-i > max {
				max = j + 1 - i
				prime = sum
			}
			sum += primes[j+1]
		}
	}

	return prime
}
Example #2
0
func E10() uint64 {
	var sum uint64
	sieve := utils.Sieve(2000000)
	for i, k := range sieve {
		if !k {
			sum += uint64(i)
		}
	}
	return sum
}