Fill in the numbers according to the rules: 2 and 1 / 4, 3 and 1 / 9, 5 and 2 / 16, 7 and 3 / 25, 11 and 5 / 36, 13 and 8 / 49, () /?

Fill in the numbers according to the rules: 2 and 1 / 4, 3 and 1 / 9, 5 and 2 / 16, 7 and 3 / 25, 11 and 5 / 36, 13 and 8 / 49, () /?

The integer part is prime, so the exponent after 13 is 17
If you look at the fraction part, it's easy to know that the denominator is square. 4 is 2 square. 9 is 3 square
So the denominator in brackets is the square of 8
The molecular part is the sum of the molecular parts of the first two numbers. For example, the third molecule is 2 = 1 + 1
The sixth molecule is 8 = 3 + 5, so the seventh molecule is 5 + 8 = 13
So it's 17 and 13 / 64 in brackets