# import necessary libraries
import pandas as pd

# define your series
s = pd.Series([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])

# use list comprehension and index to filter
positions = [i for i in s.index if s[i] % 3 == 0]

# convert into series and print
result = pd.Series(positions)
print(f"Positions of Multiples of 3: \n{result}")