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 Prime it remains (Posted on 2013-01-15)
What is the smallest prime remaining prime when added to its reverse?

Analytical solution preferred.

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 computer solution | Comment 1 of 4

10   for I=1 to 100
20   P=prm(I)
30   S=cutspc(str(P))
40   R=""
50   for J=1 to len(S)
60      R=mid(S,J,1)+R
70   next
80   Rev=val(R)
90   P2=P+Rev
100   if prmdiv(P2)=P2 then print P,Rev,P2
110   next

finds

`prime    rev    new prime  229     922     1151 239     932     1171 241     142     383 257     752     1009 269     962     1231 271     172     443 277     772     1049 281     182     463 439     934     1373 443     344     787 463     364     827 467     764     1231 479     974     1453 499     994     1493`

The smallest is 229.

Only primes up to the 100th prime were checked.

 Posted by Charlie on 2013-01-15 17:59:45

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