1 / 1, 1 / 2, 2 / 2, 1 / 3, 2 / 3, 3 / 3, 1 / 4, 2 / 4, 3 / 4, 4 / 4, 1 / 5, 2 / 5 -- - (find the law) what is the 25th number?

1 / 1, 1 / 2, 2 / 2, 1 / 3, 2 / 3, 3 / 3, 1 / 4, 2 / 4, 3 / 4, 4 / 4, 1 / 5, 2 / 5 -- - (find the law) what is the 25th number?

The molecular rules are: 1, 121, 231, 234, 123, 451, 23456 The 25th is 4
The law of denominator is: 1, 2233, 344, 445, 555, 667, 777 The 25th is 7
So the 25th number is 4 / 7