I think you need numpy.r_ for concanecate indices:
df.iloc[:,np.r_[0,1,51:102]]
Sample:
df = pd.DataFrame([[0] * 10], columns=list('abcdefghij'))
print (df)
a b c d e f g h i j
0 0 0 0 0 0 0 0 0 0 0
print (df.iloc[:,np.r_[0,1,5:8]])
a b f g h
0 0 0 0 0 0