Calculate Field to get weighted sum

Hi,

I m trying to make Weighted Sum on certain field.

It has to be in 12 months window size (ex, On 2023-02, it is the sum of 2022-03 ~ 2023-02).

And, each value of the month is multiplied by index (like 1, 2, 3 ... 12)

So, the formula looks like,

For i = 1 ~ 12, Σ i * Xi (Xi is the value of the month)

I tried window_sum and running_sum ... but it didn't make the result i want...

Thanks in advance!