linspace

import numpy as np

a=10
b=20
n=200

arr1 = np.array([a+(b-a)/(n-1) * (i-1) for i in range(1,n+1)])

$$a+\frac{(b-a)i}{n-1}$$ for $i=1,2,3,\dots ,n$

arr2 = np.linspace(a,b,n)

arr1[:5]

array([10.        , 10.05025126, 10.10050251, 10.15075377, 10.20100503])

arr2[:5]

array([10.        , 10.05025126, 10.10050251, 10.15075377, 10.20100503])