TESTING SNTGRL
  k=power of x in integral from 0 to 1
  n=no of points
  ans=int x**k*(k+1)-1
 k= 1 n= 20 ans= -2.22044605E-16
 k= 1 n= 40 ans=  0.
 k= 1 n= 60 ans=  0.
 k= 1 n= 80 ans=  0.
 
 k= 2 n= 20 ans=  0.
 k= 2 n= 40 ans=  2.22044605E-16
 k= 2 n= 60 ans=  2.22044605E-16
 k= 2 n= 80 ans=  0.
 
 k= 3 n= 20 ans=  0.
 k= 3 n= 40 ans=  0.
 k= 3 n= 60 ans=  2.22044605E-16
 k= 3 n= 80 ans=  0.
 
 k= 4 n= 20 ans=  4.94791667E-06
 k= 4 n= 40 ans=  2.84830729E-07
 k= 4 n= 60 ans=  5.46553498E-08
 k= 4 n= 80 ans=  1.70389811E-08
 
 k= 5 n= 20 ans=  1.484375E-05
 k= 5 n= 40 ans=  8.54492188E-07
 k= 5 n= 60 ans=  1.63966049E-07
 k= 5 n= 80 ans=  5.11169433E-08