SGU 294 He ' s Circles

Test instructions: A necklace has n beads and each bead is black or white. How many different kinds of necklaces are there?

Note that the number of n is very large, therefore, we enumerate I (1<=i<=n), so that l=n/i, to find the Euler function of L, then these numbers and L coprime, so gcd (k,n) =i k A total of L Euler functions, this is a very clever way of conversion, and this problem requires high precision. The final answer is the Euler function of σ (2^i*k)/n,k (n/i).

Code: Too long dare not fight, afraid to change a day can not be changed out.

SGU 294 He ' s Circles