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fermatslibrary's profile
Fermat's Library
Fermat's Library
Fermat's Library
@fermatslibrary

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Fermat's Library

@fermatslibrary

A platform for illuminating academic papers. We publish an annotated paper every week. Our chrome extension for arXiv: https://fermatslibrary.com/librarian 

fermatslibrary.com
Joined September 2015

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    Fermat's Library‏ @fermatslibrary 13 Aug 2018
    • Report Tweet
    • Report NetzDG Violation

    Numbers that can be expressed using their own digits together with: +,-,x,:,^ and () are called Friedman numberspic.twitter.com/IlNtJQbVtp

    5:50 AM - 13 Aug 2018
    • 1,394 Retweets
    • 4,336 Likes
    • KEVAL btorit Siranut Srinivasa Raghava K Ravi of House Desai jck-chipulu Dan Prick DestinyJor 卐
    35 replies 1,394 retweets 4,336 likes
      1. New conversation
      2. Rachel Bowen‏ @Rachel__Bowen 13 Aug 2018
        • Report Tweet
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        Replying to @fermatslibrary

        Do the digits have to be in the correct order?

        1 reply 0 retweets 6 likes
      3. AVE !‏ @aveilleur 13 Aug 2018
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        Replying to @Rachel__Bowen @fermatslibrary

        Only for "nice" or "orderly" Friedman numbers. For example: 127 = −1 + 2^7 is a nice Friedman number.

        1 reply 0 retweets 17 likes
      4. 1 more reply
      1. New conversation
      2. Praveen J‏ @jpraveensn 13 Aug 2018
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        Replying to @fermatslibrary

        5120 = 5*2^10

        1 reply 0 retweets 14 likes
      3. AVE !‏ @aveilleur 13 Aug 2018
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        Replying to @jpraveensn @fermatslibrary

        1024 = (4 − 2)^10

        0 replies 0 retweets 7 likes
      4. End of conversation
      1. New conversation
      2. Luis Batalha  🇵🇹 🇺🇸‏ @luismbat 13 Aug 2018
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        Replying to @fermatslibrary

        All Roman numerals with more than one symbol are Friedman numbers (just insert + signs into the numeral). The number 8 is an example of a non-trivial Friedman number VIII = (V - I) × II

        1 reply 0 retweets 19 likes
      3. Shinnosuke  🎗️ #FreeCatalanPoliticalPrisoners‏ @shinnoshanno 13 Aug 2018
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        Replying to @luismbat @fermatslibrary

        Not true for IV, but -I+V=IV

        0 replies 0 retweets 4 likes
      4. End of conversation
      1. New conversation
      2. menjaraz‏ @menjaraz 13 Aug 2018
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        Replying to @fermatslibrary

        #Math How to tell a number is a Friedman's one? Is there an appropriate algorithm for the purpose?

        1 reply 1 retweet 5 likes
      3. Florian Cassayre‏ @flomine68 13 Aug 2018
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        Replying to @menjaraz @fermatslibrary

        Nah, unless there exist a non trivial trick this problem is rather hard (essentially bruteforce)

        2 replies 0 retweets 3 likes
      4. 3 more replies
      1. Vincent Pantal 🍩ni‏ @panlepan 13 Aug 2018
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        Replying to @fermatslibrary

        Vincent Pantal 🍩ni Retweeted Vincent Pantal 🍩ni

        Thread on Friedman numbers.https://twitter.com/panlepan/status/922737702012891137?s=19 …

        Vincent Pantal 🍩ni added,

        Vincent Pantal 🍩ni @panlepan
        A Friedman number is an integer, which can be expressed using all its own digits in combination with any of the ops: +, −, ×, ÷ ,^ eg 25=5² pic.twitter.com/nDLxuMpRm5
        Show this thread
        0 replies 3 retweets 2 likes
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      1. ∑∅Z‏ @zubie7a 13 Aug 2018
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        Replying to @fermatslibrary

        Not a Friedman Number but I once found out about this by accident: 365*2-1 == (36-5*2+1) * (36-5*2+1)

        0 replies 0 retweets 7 likes
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