> numberBigInt = numberBigInt.minus(1)
https://github.com/geonnave/primg/blob/master/index.html#L82
Could go double as fast subtracting 2 instead of 1 (why try the even numbers).
https://github.com/geonnave/primg/blob/master/index.html#L82
Could go double as fast subtracting 2 instead of 1 (why try the even numbers).