Find the smallest prime that remains prime
when added to its reversal
P&P solution preferred
As two odd numbers added together will be even and the only even prime is 2, the smallest prime that remains prime must be in the form 2XN where X represents zero or more digits and N is an odd digit other than 3 or 5 (as, but for the number 5, no prime number can end in 5; and 3+2 = 5).
Iterating through the possible primes from lowest upward, the fourth prime number that passes the aforementioned restrictions is 229.
229 + 922 = 1151 is prime.
Edited on September 24, 2018, 4:26 pm
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Posted by Dej Mar
on 2018-09-24 16:10:19 |
answer
