• Digit Permutation

    From David Entwistle@qnivq.ragjvfgyr@ogvagrearg.pbz to rec.puzzles on Tue May 19 16:47:08 2026
    From Newsgroup: rec.puzzles

    Chat GPT came up with an interesting question. I have modified it slightly
    to involve some different options. I believe I have solutions, for each
    part, derived programmatically. ChatGPT suggests a more sophisticated
    solution for part f).

    Questions:

    a) Find the smallest positive integer n, such that 2n is a digit-
    permutations of n?

    b) Find the smallest positive integer n, such that 3n, is a digit-
    permutations of n?

    c) Find the smallest positive integer n, such that 4n is a digit-
    permutations of n?

    d) Find the smallest positive integer n, such that 5n is a digit-
    permutations of n?

    e) Find the smallest positive integer n, such that 6n is a digit-
    permutations of n?

    f) Find the smallest positive integer n, such that 2n, 3n, 4n, 5n, and 6n
    are all digit-permutations of n?
    --
    David Entwistle
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  • From Ilan Mayer@user4643@newsgrouper.org.invalid to rec.puzzles on Wed May 20 13:31:08 2026
    From Newsgroup: rec.puzzles


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

    Chat GPT came up with an interesting question. I have modified it slightly to involve some different options. I believe I have solutions, for each part, derived programmatically. ChatGPT suggests a more sophisticated solution for part f).

    Questions:

    a) Find the smallest positive integer n, such that 2n is a digit- permutations of n?

    b) Find the smallest positive integer n, such that 3n, is a digit- permutations of n?

    c) Find the smallest positive integer n, such that 4n is a digit- permutations of n?

    d) Find the smallest positive integer n, such that 5n is a digit- permutations of n?

    e) Find the smallest positive integer n, such that 6n is a digit- permutations of n?

    f) Find the smallest positive integer n, such that 2n, 3n, 4n, 5n, and 6n are all digit-permutations of n?


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    2 * 125874 = 251748

    3 * 1035 = 3105

    4 * 1782 = 7128

    5 * 142857 = 714285

    6 * 1386 = 8316

    2 * 142857 = 285714
    3 * 142857 = 428571
    4 * 142857 = 571428
    5 * 142857 = 714285
    6 * 142857 = 857142
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  • From David Entwistle@qnivq.ragjvfgyr@ogvagrearg.pbz to rec.puzzles on Wed May 20 17:30:26 2026
    From Newsgroup: rec.puzzles

    On Wed, 20 May 2026 13:31:08 GMT, Ilan Mayer wrote:

    SPOILER

    Well done.

    ChapGPT provided the following commentary on the solution of part f),
    which seems illuminating.

    Rnpu cebqhpg vf n crezhgngvba (n plpyvp ebgngvba) bs 142857, fb gur
    pbaqvgvba ubyqf.

    Jul guvf vf gur fznyyrfg (fxrgpu):

    Vs 2a vf n crezhgngvba bs a gura 2a rei a (zbq 9), fb a rei 0 (zbq 9) rCo a
    vf qvivfvoyr ol 9.
    Gur jryy-xabja ercrngvat qrpvzny sbe 1/7 = 0.142857142857... cebqhprf
    gur 6-qvtvg plpyvp ahzore 142857 jubfr zhygvcyrf 2rCo6 ner vgf plpyvp ebgngvbaf; guvf tvirf n inyvq rknzcyr.
    Bar pna purpx gung ab fznyyre ahzore (jvgu srjre guna 6 qvtvgf) pna fngvfsl gur pbafgenvagf (qvtvg-fhz naq qvtvg-pbhag pneel pbafgenvagf sbepr
    ng yrnfg 6 qvtvgf), fb 142857 vf gur zvavzny fbyhgvba.
    --
    David Entwistle
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