Function Twin

math/prime/twin.go:17–22

This function returns twin prime for given number returns (n + 2) if both n and (n + 2) are prime -1 otherwise

(n int)

// returns (n + 2) if both n and (n + 2) are prime
// -1 otherwise
func Twin(n int) (int, bool) {
	if OptimizedTrialDivision(int64(n)) && OptimizedTrialDivision(int64(n+2)) {
		return n + 2, true
	}
	return -1, false
}