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PROJECT EULER · #0552

Chinese Leftovers II

Statement only · UnsolvedOriginal problem ↗

Let An be the smallest positive integer satisfying Anmodpi=i for all 1in, where pi is the i-th prime.
For example A2=5, since this is the smallest positive solution of the system of equations

  • A2mod2=1
  • A2mod3=2

The system of equations for A3 adds another constraint. That is, A3 is the smallest positive solution of

  • A3mod2=1
  • A3mod3=2
  • A3mod5=3

and hence A3=23. Similarly, one gets A4=53 and A5=1523.

Let S(n) be the sum of all primes up to n that divide at least one element in the sequence A.
For example, S(50)=69=5+23+41, since 5 divides A2, 23 divides A3 and 41 divides A10=5765999453. No other prime number up to 50 divides an element in A.

Find S(300000).

Write-up coming later

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