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 Reversal creates average (Posted on 2018-10-10)
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 No Rating

 Subject Author Date re(2): computer soln Charlie 2018-10-11 08:26:11 re(2): computer soln Ady TZIDON 2018-10-11 07:15:06 re: computer soln broll 2018-10-11 03:49:10 corrected Steven Lord 2018-10-10 14:21:02 re: computer soln Charlie 2018-10-10 11:37:03 re: computer soln (agree on solution--spoiler present) Charlie 2018-10-10 11:08:03 computer soln Steven Lord 2018-10-10 08:57:25

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