Auto-populate stair calculation formula?

Hoping someone can help me out here. I have an Excel sheet with 100's of rows and about 60 columns where I am needing to replicate this formula without manually keying in every time.

The formula is shown below and it's basically a stair step sum of numbers.

ExcelFormula.PNG

When I drag the column down to copy the formula it turns into this:

ExcelFormulaError.PNG

It doesn't include G2 like I need as seen below for what it should look like:

ExcelFormula3.PNG

Any help would be appreciated with this!

Hi, if you can use VBA I will propose User Defined Function, in short UDF.
The function code in the VBA module

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On the sheet, in B2

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and then drag down.