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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.

User: Mia DeStefano

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Mia DeStefano has authored 3 sequences.

A347637 Table read by ascending antidiagonals. T(n, k) is the minimum number of pebbles such that any assignment of those pebbles on a complete graph with n vertices is a next-player winning game in the two-player impartial (k+1, k) pebbling game. T(n, k) for n >= 5 and k >= 1.

Original entry on oeis.org

7, 13, 15, 9, 21, 21, 15, 17, 35, 27, 11, 25, 25, 37, 33, 17, 21, 41, 33, 59, 39, 13, 29, 31, 45, 41, 53
Offset: 5

Keywords

Comments

A (k+1, k) pebbling move involves removing k + 1 pebbles from a vertex in a simple graph and placing k pebbles on an adjacent vertex.
A two-player impartial (k+1, k) pebbling game involves two players alternating (k+1, k) pebbling moves. The first player unable to make a move loses.
T(3, k) = A016921(k) for k >= 0. The proof will appear in a paper that is currently in preparation.
It is conjectured that T(4, k) for odd k>=3 is infinite, so we start with n = 5.
T(5, k) = A346197(k) for k >= 1.
T(n, 1) = A340631(n) for n >= 3.
T(n, 2) = A346401(n) for n >= 3.

Examples

			The data is organized in a table beginning with row n = 5 and column k = 1. The data is read by ascending antidiagonals. The formula binomial(n + k - 5, 2) + k converts the indices from table form to sequence form.
The table T(n, k) begins:
  [n/k]  1   2   3   4   5   6  ...
  ---------------------------------
  [ 5]   7, 15, 21, 27, 33, 39, ...
  [ 6]  13, 21, 35, 37, 59, 53, ...
  [ 7]   9, 17, 25, 33, 41, 51, ...
  [ 8]  15, 25, 41, 45, 61, ...
  [ 9]  11, 21, 31, 41, 51, ...
  [10]  17, 29, 45, 53, 71, ...
  [11]  13, 25, 37, 49, 61, ...
  [12]  19, 33, 51, ...
  [13]  15, 29, 43, ...
  [14]  21, 37, ...
  [15]  17, 33, ...
  [16]  23, 41, ...
		

References

  • E. R. Berlekamp, J. H. Conway, and R. K. Guy, Winning Ways for Your Mathematical Plays, Vol. 1, CRC Press, 2001.

Crossrefs

Programs

  • Mathematica
    (* m represents number of vertices in the complete graph. Each pebbling move removes k+1 pebbles from a vertex and adds k pebbles to an adjacent vertex. *)
    Do[(* Given m and a, list all possible assignments with a pebbles. *)
    alltuples[m_, a_] := IntegerPartitions[a + m, {m}] - 1;
    (* Given an assignment, list all resultant assignments after one pebbling move; only works for m>=3. *)
    pebblemoves[config_] :=
      Block[{m, temp}, m = Length[config];
       temp = Table[config, {i, m (m - 1)}] +
         Permutations[Join[{-(k + 1), k}, Table[0, {i, m - 2}]]];
       temp = Select[temp, Min[#] >= 0 &];
       temp = ReverseSort[DeleteDuplicates[ReverseSort /@ temp]]];
    (* Given m and a, list all assignments that are P-games. *)
    Plist = {};
    plist[m_, a_] :=
      Block[{index, tuples},
       While[Length[Plist] < m, index = Length[Plist];
        AppendTo[Plist, {{Join[{1}, Table[0, {i, index}]]}}]];
       Do[AppendTo[Plist[[m]], {}]; tuples = alltuples[m, i];
        Do[If[
          Not[IntersectingQ[pebblemoves[tuples[[j]]],
            If[i > 2, Plist[[m, i - 1]], {}]]],
          AppendTo[Plist[[m, i]], tuples[[j]]]], {j, Length[tuples]}], {i,
          Length[Plist[[m]]] + 1, a}]; Plist[[m, a]]];
    (* Given m, print out the minimum a such that there are no P-games with a pebbles *)
    Do[a = 1; While[plist[m, a] != {}, a++];
      Print["k=", k, " m=", m, " a=", a], {m, 5, 10}], {k, 1, 6}]

A346197 a(n) is the minimum number of pebbles such that any assignment of those pebbles on K_5 is a next-player winning game in the two-player impartial (n+1,n) pebbling game.

Original entry on oeis.org

7, 15, 21, 27, 33, 39, 47, 53, 59, 67, 73, 79, 87, 93, 99, 107, 113, 119, 127, 133, 139
Offset: 1

Keywords

Comments

For n>0, an (n+1,n) pebbling move involves removing n+1 pebbles from a vertex in a simple graph and placing n pebbles on an adjacent vertex.
A two-player impartial (n+1,n) pebbling game involves two players alternating (n+1,n) pebbling moves. The first player unable to make a move loses.

Examples

			For n=1, a(1)=7 is the least number of pebbles for which every (2,1) game on K_5 is a next-player winning game regardless of assignment.
		

References

  • E. R. Berlekamp, J. H. Conway, and R. K. Guy, Winning Ways for Your Mathematical Plays, Vol. 1, CRC Press, 2001.

Crossrefs

Programs

  • Mathematica
    Do[remove = k + 1; add = k;
    (*Given n and m, list all possible assignments.*)
    alltuples[n_, m_] := IntegerPartitions[m + n, {n}] - 1;
    (*Given an assignment, list all resultant assignments after one pebbling move; only work for n>=3.*)
    pebblemoves[config_] :=  Block[{n, temp},
        n = Length[config];
        temp = Table[config, {i, n (n - 1)}] +
            Permutations[Join[{-remove, add}, Table[0, {i, n - 2}]]];
        temp = Select[temp, Min[#] >= 0 &];
        temp = ReverseSort[DeleteDuplicates[ReverseSort /@ temp]]];
    (*Given n and m, list all assignments that are P-games.*)
    Plist = {};
    plist[n_, m_] :=  Block[{index, tuples},
        While[Length[Plist] < n, index = Length[Plist];
            AppendTo[Plist, {{Join[{1}, Table[0,{i,index}]]}}]];
        Do[AppendTo[Plist[[n]], {}]; tuples = alltuples[n, i];
            Do[If[Not[IntersectingQ[pebblemoves[tuples[[j]]],
                    If[i > (remove - add), Plist[[n, i - (remove - add)]], {}]]],
                AppendTo[Plist[[n, i]], tuples[[j]]]], {j, Length[tuples]}],
        {i, Length[Plist[[n]]] + 1, m}]; Plist[[n, m]]];
    Do[m = 1; While[plist[n, m] != {}, m++]; Print[" k=", k, " m=", m], {n, 5, 5}],
    {k, 1, 21}]

A346401 a(n) is the minimum number of pebbles such that any assignment of those pebbles on a complete graph with n vertices is a next-player winning game in the two-player impartial (3, 2) pebbling game.

Original entry on oeis.org

13, 21, 15, 21, 17, 25, 21, 29, 25, 33, 29, 37, 33, 41, 37, 45, 41, 49, 45, 53, 49, 57
Offset: 3

Keywords

Comments

A (3,2) pebbling move involves removing 3 pebbles from a vertex in a simple graph and placing 2 pebbles on an adjacent vertex.
A two-player impartial (3,2) pebbling game involves two players alternating (3,2) pebbling moves. The first player unable to make a move loses.

Examples

			For n=6, a(6)=21 is the least number of pebbles for which every (3,2) game on K_6 is a next-player winning game regardless of assignment.
For n=7, a(7)=17 is the least number of pebbles for which every (3,2) game on K_7 is a next-player winning game regardless of assignment.
		

References

  • E. R. Berlekamp, J. H. Conway, and R. K. Guy, Winning Ways for Your Mathematical Plays, Vol. 1, CRC Press, 2001.

Crossrefs

Programs

  • Mathematica
    remove = 3; add = 2;
    (*Given n and m,list all possible assignments.*)
    alltuples[n_, m_] := IntegerPartitions[m + n, {n}] - 1;
    (*Given an assignment,list all resultant assignments after one pebbling move; only work for n>=3.*)
    pebblemoves[config_] := Block[{n, temp},
        n = Length[config];
        temp = Table[config, {i, n (n - 1)}] +
            Permutations[Join[{-remove, add}, Table[0, {i, n - 2}]]];
        temp = Select[temp, Min[#] >= 0 &];
        temp = ReverseSort[DeleteDuplicates[ReverseSort /@ temp]]];
    (*Given n and m,list all assignments that are P-games.*)
    Plist = {};
    plist[n_, m_] :=  Block[{index, tuples},
        While[Length[Plist] < n, index = Length[Plist];
            AppendTo[Plist, {{Join[{1}, Table[0, {i, index}]]}}]];
        Do[AppendTo[Plist[[n]], {}]; tuples = alltuples[n, i];
            Do[If[Not[IntersectingQ[pebblemoves[tuples[[j]]],
                    If[i > (remove - add), Plist[[n, i - (remove - add)]], {}]]],
                AppendTo[Plist[[n, i]], tuples[[j]]]], {j, Length[tuples]}],
        {i, Length[Plist[[n]]] + 1, m}]; Plist[[n, m]]];
    Do[m = 1; While[plist[n, m] != {}, m++]; Print[" n=", n, " m=", m], {n, 3, 24}]

Formula

a(n) = 2n+3 when n >= 7 is odd (conjectured).
a(n) = 2n+9 when n >= 6 is even (conjectured).