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.

A379758 Number of sequences in which the games of a fully symmetric single-elimination tournament with 2^n teams can be played if arbitrarily many arenas are available.

Original entry on oeis.org

1, 3, 365, 1323338487, 1119556146543237253601352961, 3414445659328795239581367793706562556567987857578516541118092297328702035
Offset: 1

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Author

Noah A Rosenberg, Jan 01 2025

Keywords

Comments

a(n) is also the number of tie-permitting labeled histories for a fully symmetric labeled topology with 2^n leaves.

Examples

			For n=2 and a tournament with structure ((A,B),(C,D)), game (A,B) can be played before, after, or simultaneously with game (C,D), producing a(2)=3.
		

Crossrefs

Cf. A056972 (game sequences with only one arena).
Row sums of A380166.

Formula

a(n) = Sum_{k=n..2^n-1} A380166(n,k).

A380767 Number of sequences in which the games of a single-elimination tournament with n teams can be played if arbitrarily many arenas are available and the tournament bracket is chosen to be the bracket with the largest such number of sequences.

Original entry on oeis.org

1, 1, 3, 5, 19, 63, 365, 1199, 7177, 36209, 295355, 1652085, 15193115, 114570449, 1323338487, 8732267521, 93577466255, 822198823101, 10952623368043
Offset: 2

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Author

Noah A Rosenberg, Feb 02 2025

Keywords

Comments

a(n) is also the number of tie-permitting labeled histories for the labeled topology with n leaves that possesses the largest number of tie-permitting labeled histories.
Terms for n=2 to 8 appear in Tables 2 and 3 of King & Rosenberg (2023); terms for n=9 to 20 are supplied by Emily H. Dickey.

Examples

			For 5 teams A, B, C, D, E, the maximizing tournament structure is ((A,B),((C,D),E)). The 5 game sequences enumerated are: (1) Game (A,B), then game (C,D), then game ((C,D),E), then game ((A,B),((C,D),E)); (2) Game (C,D), then game (A,B), then game ((C,D),E), then game ((A,B),((C,D),E)); (3) Game (C,D), then game ((C,D),E), then game (A,B), then game ((A,B),((C,D),E)); (4) Game (A,B) and game (C,D) simultaneously, then game ((C,D),E), then game ((A,B),((C,D),E)); (5) Game (C,D), then game (A,B) and game ((C,D),E) simultaneously, then game ((A,B),((C,D),E)).
		

Crossrefs

Cf. A379758 and A380166 for game sequences with fully symmetric tournaments.
Cf. A001190.

Formula

a(n) is computed as the maximum over unlabeled binary rooted trees T with n leaves (trees in the set enumerated by A001190) of the quantity computed for tree T in eq. 3 of King & Rosenberg (2023) (by summing terms in Theorem 3).

A378855 Triangle read by rows: T(n,k) is the number of sequences in which the games of a single-elimination tournament with n teams can be played if arbitrarily many arenas are available, the tournament bracket is chosen to the bracket with the largest such number of sequences, and the number of distinct times at which games are played is k, log_2(n) <= k <= n-1.

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 0, 2, 3, 0, 0, 2, 9, 8, 0, 0, 1, 12, 30, 20, 0, 0, 1, 22, 102, 160, 80, 0, 0, 0, 10, 114, 380, 485, 210, 0, 0, 0, 10, 198, 1100, 2495, 2478, 896, 0, 0, 0, 5, 204, 1930, 7260, 12810, 10640, 3360, 0, 0, 0, 5, 344, 4890, 27110, 72702
Offset: 2

Views

Author

Noah A Rosenberg, Feb 10 2025

Keywords

Comments

T(n,k) is also the number of tie-permitting labeled histories for a labeled topology with n leaves and exactly k times at which events take place, when the labeled topology is chosen to be the labeled topology with the largest number of tie-permitting labeled histories across all labeled topologies with n leaves.
The first row has n=2. Terms for n=2 to 8 appear in Tables 2 and 3 of King & Rosenberg (2023); terms for n=9 to 16 are supplied by Emily H. Dickey.

Examples

			Triangle begins:
  1;
  0, 1;
  0, 1, 2;
  0, 0, 2,  3;
  0, 0, 2,  9,   8;
  0, 0, 1, 12,  30,    20;
  0, 0, 1, 22, 102,   160,     80;
  0, 0, 0, 10, 114,   380,    485,     210;
  0, 0, 0, 10, 198,  1100,   2495,    2478,      896;
  0, 0, 0,  5, 204,  1930,   7260,   12810,    10640,      3360;
  0, 0, 0,  5, 344,  4890,  27110,   72702,   101024,     70080,     19200;
  0, 0, 0,  2, 278,  6360,  53000,  211365,   451164,    529116,    321600,     79200;
		

Crossrefs

Row sums are A380767.
Cf. A380166 for the triangle if n is a power of 2.
Entries T(n,n-1) follow A056971.

Formula

The maximum is computed over unlabeled binary rooted trees T with n leaves (trees in the set enumerated by A001190) of the quantity computed for tree T in eq. 3 of King & Rosenberg (2023). This maximum gives the row sum, tabulated in A380767. For the tree that generates the maximum, the row entries are computed as the specific terms described in Theorem 3 of King & Rosenberg (2023) (and summed in eq. 3).
Showing 1-3 of 3 results.