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.

Showing 1-3 of 3 results.

A007709 Number of winning (or reformed) decks at Mousetrap.

Original entry on oeis.org

1, 1, 2, 6, 15, 84, 330, 1812, 9978, 65503, 449719, 3674670, 28886593, 266242729, 2527701273, 25749021720
Offset: 1

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Author

Keywords

References

  • A. M. Bersani, "Reformed permutations in Mousetrap and its generalizations," Preprint Me.Mo.Mat. n. 15/2005.
  • R. K. Guy, Unsolved Problems Number Theory, E37.
  • R. K. Guy and R. J. Nowakowski, "Mousetrap," in D. Miklos, V. T. Sos and T. Szonyi, eds., Combinatorics, Paul Erdős is Eighty. Bolyai Society Math. Studies, Vol. 1, pp. 193-206, 1993.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Extensions

Better description and more terms from Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 09 2007
One more term from Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 24 2008

A028305 Triangle of numbers of permutations eliminating just k cards out of n in game of Mousetrap.

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 2, 2, 0, 2, 9, 6, 3, 0, 6, 44, 31, 19, 11, 0, 15, 265, 180, 105, 54, 32, 0, 84, 1854, 1255, 771, 411, 281, 138, 0, 330, 14833, 9949, 6052, 3583, 2057, 1366, 668, 0, 1812, 133496, 89162, 55340, 32135, 19026, 12685, 6753, 4305, 0, 9978, 1334961, 886837, 547922, 331930, 193538, 117323, 79291, 45536, 25959, 0, 65503
Offset: 0

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Author

Keywords

Comments

Triangle T(n,k), 0 <= k <= n

Examples

			Triangle begins:
     1,
     0,    1,
     1,    0,   1,
     2,    2,   0,   2,
     9,    6,   3,   0,   6,
    44,   31,  19,  11,   0,  15,
   265,  180, 105,  54,  32,   0, 84,
  1854, 1255, 771, 411, 281, 138,  0, 330,
  ...
		

References

  • R. K. Guy, Unsolved Problems Number Theory, E37.
  • R. K. Guy and R. J. Nowakowski, "Mousetrap," in D. Miklos, V. T. Sos and T. Szonyi, eds., Combinatorics, Paul Erdős is Eighty. Bolyai Society Math. Studies, Vol. 1, pp. 193-206, 1993.
  • S. Washburn, T. Marlowe and C. T. Ryan, Discrete Mathematics, Addison-Wesley, 1999, page 326.

Crossrefs

Programs

  • Maple
    A028305:=proc(n)
      local P, j, M, K, A, i, K_neu, k, m;
      P:=combinat[permute](n):
      for j from 0 to n do
        M[j]:=0:
      od:
      for j from 1 to nops(P) do
        K:=P[j]:
        A:=[]:
        for i while nops(K)>0 do
          K_neu:=[]:
          for k from 1 to n do
            m:=nops(K);
            if k mod m = 0 then
              if K[m]=k then
                K_neu:=[seq(K[j],j=1..m-1)];
                A:=[op(A),k];
              else next;
              fi;
            else
              if K[k mod m]=k then
                K_neu:=[seq(K[j],j=(k mod m)+1..m),seq(K[j],j=1..(k mod m)-1)];
                A:=[op(A),k];
              else next;
              fi;
            fi;
            if nops(K_neu)<>0 then break; fi;
          od;
          if nops(K_neu)<>0 then
            K:=K_neu;
          else break;
          fi;
        od:
        M[nops(A)]:=M[nops(A)]+1;
      od:
      seq(M[j],j=0..n);
    end:
    # Martin Renner, Sep 03 2015

Formula

T(n,0) = A000166(n), T(n,1) = A007710(n), T(n,n-1) = A000004(n) = 0, T(n,n) = A007709(n).

Extensions

a(36)-a(65) from Martin Renner, Sep 02 2015

A127966 a(n) = number of 4-times (but not 5-times) reformable permutation of {1,...,n}.

Original entry on oeis.org

2, 1, 1, 4, 14, 57
Offset: 11

Views

Author

Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 09 2007

Keywords

Comments

For n=16 we have the first example of a 5-reformed (but not 6-reformed) permutation: 1, 16, 12, 15, 6, 8, 14, 10, 9, 3, 4, 11, 13, 2, 7, 5 - Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 24 2008

References

  • A. M. Bersani, ``Reformed permutations in Mousetrap and its generalizations,'' Preprint Me.Mo.Mat. n. 15/2005.
  • R. K. Guy and R. J. Nowakowski, ``Mousetrap,'' in D. Miklos, V.T. Sos and T. Szonyi, eds., Combinatorics, Paul Erdős is Eighty. Bolyai Society Math. Studies, Vol. 1, pp. 193-206, 1993.

Crossrefs

Extensions

One more term from Alberto M. Bersani (bersani(AT)dmmm.uniroma1.it), Feb 24 2008
Showing 1-3 of 3 results.