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Posted 2021-01-03 coder-tcm

A square_free integer is an integer which is indivisible by any square number except 1.
F or example 6=2*3 is square-free ,but 12=2^2*3 is not because 2^2 is a square number .
Some integers could be dwecomposed into product of two square-free integers.there may be mpore than one decomposition ways.
For example 6=1*6=6*1=2*3=3*2,n=ab and n=ba are considered different if a!=b.
f(n)is the number of decomposition ways that n=ab such that a and b are square-free integer.the problem is calculating from 1 to n f(i)