Problem 124

[dawghaus4]

Let me start with a big thank you to all who have contributed to Project Euler. I am 70 years old and started programming in C++ last November. The Project Euler problems have provided a strong stimulus and motivation and I have learned much that I would not have, otherwise.

Now my first issue. Problem 124 provides this definition.

The radical of n, rad(n), is the product of distinct prime factors of n.

In the problem's example, rad(1) is given to have a value of 1. How does that come from the definition?

It would seem that a better definition would be: rad(1) = 1. If n is prime, rad(n) = n. For all other natural numbers n, rad(n) is the product of the distinct prime factors of n.

(Note the use of the. Without it, one could interpret rad(180) to have several different values, 6, 10, 15, and/or 30, all of which are products of distinct prime factors of 180. One might also include 2, 3, and 5, since the current wording doesn't require any multiplication to form a product.)

I'm sure the current wording has cause no problems, but doesn't measure up to the high caliber that I have become accustomed to seeing.

[TripleM]

In mathematics a product of an empty set is defined to be equal to 1: https://en.wikipedia.org/wiki/Empty_product

For someone unaware of this, rad(1) is specifically provided in the table so there shouldn't be any room for misunderstanding.

I agree an extra 'the' would probably be marginally better English, but again you would be hard pressed to say the current version is incorrect or able to be misunderstood given the numerous examples.

[hk]

the added.
The definition of rad(1) can be read from the table.