Needing help in creating formula that returns value using numbers between two values.

I am trying to come up with a Formula that adds values from start to finish.

Current Value E2: 200
Goal Value E3: 300

The base formula is as follows:

Formula:

=ROUND(E2^1.3)

I am looking for a formula that would give me total value from 200 to 300 but come back with 0 if Current Value is equal to Goal Value.

The current Formula I have is as follows:

Formula:

=IF(E2<F2,SUMPRODUCT(ROW(INDIRECT("A"&E2&":A"&F2))^1.3),0)

Unfortunately this doesn't take into account 200 is the starting number. If I use E2-1, it counts 200 as starting number but doesn't return a 0 when needed. When using 201 as Goal Value, it returns the sumproduct of 200^1.3 and 201^1.3.

Any help with this would be appreciated. I am also attaching a sample sheet showing what I want. The Formulas I show in here are in G2 (Base Formula) and I2 (Requested Formula).