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Reversal creates average (Posted on 2018-10-10) Difficulty: 3 of 5
Let Sp(n) be a sum of all primes from p(1) to p(n) inclusive.
Let m(n) be the average value of all those primes, i.e. m(n)= Sp(n)/n.

Find the n-th prime N such that m(n) equals the reversal of N.

Example for n=6: Sp(6)=2+3+5+7+11+13= 41; m(6)=41/6; not the reversal of 13, that is 31 .
So 13 is not our prime.
Another 2-digit number is.

Find it.

Are there any additional i.e. "numbers over 100" solutions?

No Solution Yet Submitted by Ady TZIDON    
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Comments: ( Back to comment list | You must be logged in to post comments.)
re(2): computer soln Comment 7 of 7 |
(In reply to re: computer soln by broll)

Steven, does the version of Fortran you use have a double precision real numeric type? If so, use that instead of the ordinary single precision real type.
  Posted by Charlie on 2018-10-11 08:26:11

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