Remove the leading 3 and the trailing term of 1/4 increasing in power.

You are left with this (in the 4th line):

1 3 5 1

- - - -

2 4 6 7

The pattern I see is that, starting from the top left and reading numerator, denominator, numerator, denominator and so on gives: 1 2 3 4 5 6 7 if you ignore the last numerator.

I may have it wrong, but that looks like the pattern.