igral.a60 :

integral of x^2 for  0 <= x <= 1

                n      sum
                2     5.0000000e-01 
                5     3.4375000e-01 
               10     2.3593964e-01 
               20     3.3379501e-01 
               50     3.1340683e-01 
              100     3.3335034e-01 
              150     3.3334084e-01