cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A014588 Nim function for Take-a-Fibonacci-Game (a subtraction game).

Original entry on oeis.org

0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 2
Offset: 0

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Author

Keywords

Comments

This game is also called Fibonacci nim, but there is also a different game with the same name. Its winning positions (the indexes of zeros in this sequence) are A001581 and its (much sparser) odd winning positions are A120904. - David Eppstein, Jun 14 2018
Concerning the January 1997 dissertation of Achim Flammenkamp, his home page (currently http://wwwhomes.uni-bielefeld.de/cgi-bin/cgiwrap/achim/index.cgi) has the link shown below, and a comment that a book was published in July 1997 by Hans-Jacobs-Verlag, Lage, Germany with the title Lange Perioden in Subtraktions-Spielen (ISBN 3-932136-10-1). This is an enlarged study (more than 200 pages) of his dissertation. - N. J. A. Sloane, Jul 25 2019

References

  • R. K. Guy, Unsolved Problems in Number Theory, E26.
  • David L. Silverman, Your Move, McGraw Hill, 1971, page 211. Reprinted by Dover Books, 1991 (mentions this game).

Crossrefs

Programs

  • Sage
    def A014588(max) :
        res = []
        for i in range(max+1) :
            moves = list({res[i-f] for f in fibonacci_xrange(1,i+1)})
            moves.sort()
            k = len(moves)
            mex = next((j for j in range(k) if moves[j] != j), k)
            res.append(mex)
        return res
    # Eric M. Schmidt, Jul 20 2013, corrected Eric M. Schmidt, Apr 24 2019

A120904 Odd winning positions in Fibonacci nim.

Original entry on oeis.org

169, 635, 723, 791, 2697, 3057, 3067, 3073, 3079, 3089, 3099, 3167, 3183, 3193, 3303, 3371, 3427, 11419, 11435, 11451, 11461, 11529, 11555, 12973, 12989, 13051, 13057, 13067, 13109, 13135, 13155, 13161, 13171, 13187, 13863, 14077, 14329, 14355, 14617, 14643
Offset: 1

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Author

Keywords

Comments

The values appear to cluster; see the plot below. This sequence is also the sequence of odd terms that appear in the lexicographically least subset of the positive integers that does not contain two terms with difference equal to a Fibonacci number; see the comments in A001581. - Boon Suan Ho, Oct 05 2023

Crossrefs

Cf. A001581.

Extensions

a(39)-a(40) from Charlie Neder, Feb 23 2019
Showing 1-2 of 2 results.