Sounds like just a bit of fun to me. For one, emirp-hood depends on the number base, which means it’s not intrinsic to the number, but depends on some arbitrary choice of representation. Generally, things like that don’t indicate anything deep.
I can think of a couple of things off the top of my head:
- You can reject numbers that start with 2,4,5,6 or 8 since their reverse won't be prime.
- If you're searching through a range of numbers for emirps avoid checking for the same pair twice. For example if you start at 1 and check for emirps, by the time you're checking 311 you've already checked 113 so you don't need to check 311.
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[ 0.22 ms ] story [ 49.3 ms ] thread[0] https://en.wikipedia.org/wiki/Palindromic_prime
See also: http://www.cadaeic.net/silopolis.htm
- You can reject numbers that start with 2,4,5,6 or 8 since their reverse won't be prime.
- If you're searching through a range of numbers for emirps avoid checking for the same pair twice. For example if you start at 1 and check for emirps, by the time you're checking 311 you've already checked 113 so you don't need to check 311.
https://en.wikipedia.org/wiki/Decimal
[1] https://oeis.org/A006567
[2] https://oeis.org/A080790
Fractional bases, negative bases, negative fractional bases, base e (supposed to be optimal IIRC), perhaps complex bases, summat weirder?
:D