return (x * 78913) >> 18
}

// mulByLog10Log2 returns math.Floor(x * log(10)/log(2)) for an integer x in
// the range -500 <= x && x <= +500.
//
// The range restriction lets us work in faster integer arithmetic instead of
// slower floating point arithmetic. Correctness is verified by unit tests.
func mulByLog10Log2(x int) int {
	// log(10)/log(2) ≈ 3.32192809489 ≈ 108853 / 2^15