hi
here is 3rd one that uses 2nd indicator for calculaion based on below formula:

**** Linear Time Regression: Coefficient of Determination (r squared)****
Indicator Name : "LinTimeRegrsqrd"
Input Parameters:
TimeSeries=[Close or Open or High or Low]
RegressionPeriods= Integer Value(must be >= 3 )

Calculation:

LinTimeRegr(X, n) * LinTimeRegr(X, n)

where
X = Time Series
n = Regression Periods


**** Linear Time Regression: Coefficient of Determination (r squared)****