A series of numbers are arranged according to the rule, 1 / 1 1 / 2 2 / 2 1 / 3 2 / 3 3 / 3

A series of numbers are arranged according to the rule, 1 / 1 1 / 2 2 / 2 1 / 3 2 / 3 3 / 3

law:
There is one number whose denominator is one,
There are two numbers whose denominator is two,
There are three numbers with denominator 3,
… ,
Let the number 2003 be m / N, m, n be positive integers and m ≤ n,
The denominator is n-1, the numerator is n-1, the number is 1 + 2 + 3 + +(n-1) = n (n-1) / 2 numbers,
The number whose denominator is n and numerator is n is 1 + 2 + 3 + +(n-1) + n = n (n + 1) / 2 numbers,
Then n (n-1) / 2