import numpy as np
from copy import deepcopy

v = 5

A = np.array([1,1,2,3,4])

B = deepcopy(A)

B[::2]  = v

print A
print B

B[1::2] = np.square(B[1::2])
B[1::2] = np.flipud(B[1::2])

print A
print B