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PROJECT EULER · #0646

Bounded Divisors

Statement only · SolvedOriginal problem ↗

Let n be a natural number and p1α1p2α2pkαk its prime factorisation.
Define the Liouville function λ(n) as λ(n)=(1)i=1kαi.
(i.e. 1 if the sum of the exponents αi is odd and 1 if the sum of the exponents is even. )
Let S(n,L,H) be the sum λ(d)d over all divisors d of n for which LdH.

You are given:

  • S(10!,100,1000)=1457
  • S(15!,103,105)=107974
  • S(30!,108,1012)=9766732243224.

Find S(70!,1020,1060) and give your answer modulo 1000000007.

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