• Palindromic primes

    From David Entwistle@qnivq.ragjvfgyr@ogvagrearg.pbz to rec.puzzles on Mon Nov 3 09:42:55 2025
    From Newsgroup: rec.puzzles

    Palindromic primes are prime numbers whose decimal expansion is a
    palindrome - reads the same forwards and backwards. The series of
    palindromic primes proceeds: 2, 3, 5, 7, 11, 101, 131 ... and continues through to: ... 919, 929, 10301, 10501 ... Why are there no four digit palindromic primes?
    --
    David Entwistle
    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From Ilan Mayer@user4643@newsgrouper.org.invalid to rec.puzzles on Mon Nov 3 13:25:05 2025
    From Newsgroup: rec.puzzles


    David Entwistle <qnivq.ragjvfgyr@ogvagrearg.pbz> posted:

    Palindromic primes are prime numbers whose decimal expansion is a
    palindrome - reads the same forwards and backwards. The series of palindromic primes proceeds: 2, 3, 5, 7, 11, 101, 131 ... and continues through to: ... 919, 929, 10301, 10501 ... Why are there no four digit palindromic primes?


    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER
    SPOILER

    They are all divisible by 11.
    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From Daniel@me@sc1f1dan.com to rec.puzzles on Wed Nov 5 22:32:53 2025
    From Newsgroup: rec.puzzles

    David Entwistle <qnivq.ragjvfgyr@ogvagrearg.pbz> writes:

    Palindromic primes are prime numbers whose decimal expansion is a
    palindrome - reads the same forwards and backwards. The series of palindromic primes proceeds: 2, 3, 5, 7, 11, 101, 131 ... and continues through to: ... 919, 929, 10301, 10501 ... Why are there no four digit palindromic primes?

    Wow this is interesting. I'll need a few days to stew over this.

    D
    --- Synchronet 3.21a-Linux NewsLink 1.2