SciKit Learn R-squared is very different from square of Pearson's Correlation R

Question

I have 2 numpy arrays ike so:

a = np.array([32.0, 25.97, 26.78, 35.85, 30.17, 29.87, 30.45, 31.93, 30.65, 35.49, 
              28.3, 35.24, 35.98, 38.84, 27.97,