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 1-8 of 8 results.

A007747 Number of nonnegative integer points (p_1,p_2,...,p_n) in polytope defined by p_0 = p_{n+1} = 0, 2p_i - (p_{i+1} + p_{i-1}) <= 2, p_i >= 0, i=1,...,n. Number of score sequences in a chess tournament with n+1 players (with 3 outcomes for each game).

Original entry on oeis.org

1, 2, 5, 16, 59, 247, 1111, 5302, 26376, 135670, 716542, 3868142, 21265884, 118741369, 671906876, 3846342253, 22243294360, 129793088770, 763444949789, 4522896682789, 26968749517543, 161750625450884
Offset: 0

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Author

P. Di Francesco (philippe(AT)amoco.saclay.cea.fr), N. J. A. Sloane

Keywords

Comments

A correspondence between the points in the polytope and the chess scores was found by Svante Linusson (linusson(AT)matematik.su.se):
The score sequences are partitions (a_1,...,a_n) of 2C(n,2) of length <= n that are majorized by 2n,2n-2,2n-4,...,2,0; i.e. f(n,k) := 2n+2n-2+...+(2n-2k+2)-(a_1+a_2+...+a_k) >= 0 for all k. The sequence 0=f(n,0),f(n,1),f(n,2),...,f(n,n)=0 is in the polytope. This establishes the bijection.

Examples

			With 3 players the possible scores sequences are {{0,2,4}, {0,3,3}, {1,1,4}, {1,2,3}, {2,2,2}}.
With 4 players they are {{0,2,4,6}, {0,2,5,5}, {0,3,3,6}, {0,3,4,5}, {0,4,4,4}, {1,1,4,6}, {1,1,5,5}, {1,2,3,6}, {1,2,4,5}, {1,3,3,5}, {1,3,4,4}, {2,2,2,6}, {2,2,3,5}, {2,2,4,4}, {2,3,3,4}, {3,3,3,3}}.
		

References

  • P. A. MacMahon, Chess tournaments and the like treated by the calculus of symmetric functions, Coll. Papers I, MIT Press, 344-375.

Crossrefs

Programs

  • Mathematica
    f[K_, L_, S_, X_] /; K > 1 && L <= S/K <= X + 1 - K := f[K, L, S, X] = Sum[f[K - 1, i, S - i, X], {i, L, Floor[S/K]}]; f[1, L_, S_, X_] /; L <= S <= X = 1; f[, , , ] = 0; a[n_] := f[n + 1, 0, n*(n + 1), 2*n]; Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Jul 13 2012, after Jon E. Schoenfield *)

Formula

Schoenfield (see Comments link) gives a recursive method for computing this sequence.

Extensions

More terms from David W. Wilson

A064626 Football tournament numbers: the number of possible point series for a tournament of n teams playing each other once where 3 points are awarded to the winning team and 1 to each in the case of a tie.

Original entry on oeis.org

1, 2, 7, 40, 355, 3678, 37263, 361058, 3403613, 31653377, 292547199, 2696619716
Offset: 1

Views

Author

Thomas Schulze (jazariel(AT)tiscalenet.it), Sep 30 2001

Keywords

Comments

This sequence reflects the now common 3-point rule of international football where the sum of total points awarded depends on the outcome of each match. The classical 2-point rule is equivalent to that for chess tournaments (A007747).

Examples

			For 2 teams there are 2 possible outcomes: [0, 3] and [1, 1], so a(2) = 2.
For 3 teams the outcomes are [0, 3, 6], [1, 3, 4], [3, 3, 3], [1, 1, 6], [1, 2, 4], [0, 4, 4] and [2, 2, 2], so a(3) is 7. Note that the outcome [3, 3, 3] can be obtained in two ways: (A beats B, B beats C, C beats A) or (B beats A, A beats C, C beats B).
		

Crossrefs

Extensions

a(8) and a(9) from Jon E. Schoenfield, May 05 2007
a(10) from Ming Li (dawnli(AT)ustc.edu), Jun 20 2008
a(11) from Jon E. Schoenfield, Sep 04 2008
a(12) from Jon E. Schoenfield, Dec 12 2008

A047731 Number of score sequences in tournament with n players, when 5 points are awarded in each game.

Original entry on oeis.org

1, 3, 18, 131, 1111, 10461, 105819, 1127413, 12499673, 143021541, 1678718575, 20123155604, 245521479531, 3041006378312, 38157059717410, 484209044329613, 6205758830280388, 80235572611152385
Offset: 1

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Author

Keywords

References

  • P. A. MacMahon, Chess tournaments and the like treated by the calculus o symmetric functions, Coll. Papers I, MIT Press, 344-375.

Crossrefs

A064422 Football league numbers: the possible point series for a league of n teams playing each other twice where for each match 3 points are awarded to the winning team and 1 to each in the case of a tie.

Original entry on oeis.org

1, 4, 40, 748, 13744, 238568, 4054190
Offset: 1

Views

Author

Thomas Schulze (jazariel(AT)tiscalenet.it), Sep 30 2001

Keywords

Comments

This sequence reflects the now common 3-point rule of international football where the sum of total points awarded depends on the outcome of each match. The classical 2-point rule is equivalent of that for chess tournaments (A047730).

Examples

			For 2 teams there are 4 possible outcomes: [0, 6], [1, 4], [2, 2] and [3, 3], so a(2) = 4.
		

Crossrefs

Extensions

a(6)-a(7) from Lorand Lucz, Mar 09 2012

A047733 Number of score sequences in tournament with n players, when 6 points are awarded in each game.

Original entry on oeis.org

1, 4, 25, 213, 2131, 23729, 283681, 3574222, 46866712, 634204317, 8803501719, 124799484286, 1800669899917, 26374204955323, 391331674556361, 5872226011836383, 88993282402441857, 1360552594176453319
Offset: 1

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Keywords

Crossrefs

Formula

Nonnegative integer points (p_1, p_2, ..., p_n) in polytope p_0=p_{n+1}=0, 2p_i -(p_{i+1}+p_{i-1}) <= 6, p_i >= 0, i=1, ..., n.

A047735 Number of score sequences in tournament with n players, when 8 points are awarded in each game.

Original entry on oeis.org

1, 5, 41, 459, 6033, 88055, 1379405, 22763356, 390859501, 6924877318, 125837754305, 2335060741480, 44097660919285, 845336236860344, 16415016380975679, 322349248087651458, 6392828942756895663
Offset: 1

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Author

Keywords

Crossrefs

Formula

Nonnegative integer points (p_1, p_2, ..., p_n) in polytope p_0=p_{n+1}=0, 2p_i -(p_{i+1}+p_{i-1}) <= 8, p_i >= 0, i=1, ..., n.

A047736 Number of score sequences in tournament with n players, when 9 points are awarded in each game.

Original entry on oeis.org

1, 5, 50, 630, 9285, 151652, 2658131, 49061128, 942055396, 18662965393, 379195887105, 7867076520341, 166102773740621, 3559787677138284, 77278541685154409, 1696519572528877274
Offset: 1

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Keywords

Crossrefs

Formula

Nonnegative integer points (p_1, p_2, ..., p_n) in polytope p_0=p_{n+1}=0, 2p_i -(p_{i+1}+p_{i-1}) <= 9, p_i >= 0, i=1, ..., n.

A047737 Number of score sequences in tournament with n players, when 10 points are awarded in each game.

Original entry on oeis.org

1, 6, 61, 846, 13771, 248623, 4816659, 98277943, 2086173336, 45688601782, 1026218795502, 23536101285148, 549336702455778, 13014352354398322, 312313455482385108, 7579157833713922471
Offset: 1

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Author

Keywords

Crossrefs

Formula

Nonnegative integer points (p_1, p_2, ..., p_n) in polytope p_0 = p_{n+1} = 0, 2*p_i - (p_{i+1} + p_{i-1}) <= 10, p_i >= 0, i = 1..n.
Showing 1-8 of 8 results.