Vandermonde determinants quotient

Question

I have to prove that for any integers $k_1<k_2<...<k_n$ the quotient:

$$ \frac{V_n (k_1,k_2, ..., k_n)}{V_n (1, 2, ..., n)} $$

is an integer, where:

$$ V_n (k_1,k_2, ..., k_n) = \prod_{1 \le i < j \le n} (k_j - k_i)$$

is the Vandermonde determinant.

I see that the denominator is equal to $1^{n-1} \cdot 2^{n-2} \cdot 3^{n-3} \cdot ... \cdot (n-1)^1$ but it doesn't seem to help.