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Revision History for A013976 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Number of tournaments on n nodes with a unique winner.
(history; published version)
#20 by Alois P. Heinz at Fri Sep 09 22:27:19 EDT 2022
STATUS

proposed

approved

#19 by Michael De Vlieger at Fri Sep 09 15:32:14 EDT 2022
STATUS

editing

proposed

#18 by Michael De Vlieger at Fri Sep 09 15:32:12 EDT 2022
LINKS

Yaakov Malinovsky and John W. Moon, <a href="https://arxiv.org/abs/2208.14932">On Round-Robin Tournaments with a Unique Maximum Score and Some Related Results</a>, arXiv:2208.14932 [math.CO], 2022.

STATUS

approved

editing

#17 by Alois P. Heinz at Sat Feb 29 12:25:46 EST 2020
STATUS

proposed

approved

#16 by Michel Marcus at Sat Feb 29 12:21:45 EST 2020
STATUS

editing

proposed

#15 by Michel Marcus at Sat Feb 29 12:21:34 EST 2020
AUTHOR

Michael Stob (stob(AT)udu.Calvincalvin.EDUedu)

STATUS

proposed

editing

#14 by Andrew Howroyd at Sat Feb 29 11:57:05 EST 2020
STATUS

editing

proposed

#13 by Andrew Howroyd at Sat Feb 29 11:56:08 EST 2020
DATA

1, 2, 6, 32, 600, 20544, 1218224, 160241152, 42129744768, 21293228876800, 22220602090444032, 45959959305969143808, 188702851949391611599872, 1566370829898884830446395392, 25801614282517307546368494213120, 851300764257208779000509484701188096

LINKS

Andrew Howroyd, <a href="/A013976/b013976.txt">Table of n, a(n) for n = 1..20</a>

PROG

TournamentsByScoreSeqWinners(n, isok)={

local(M=Map(Mat([x^0, 1])));

my(acc(p, v)=my(z); mapput(M, p, if(mapisdefined(M, p, &z), z+v, v)));

my(merge(r, p, v)=acc(p + sum(i=1, poldegree(p)-r-1, polcoef(p, i)*(1-x^i)), v));

my(recurse(r, p, i, q, v, e)=if(i<0, if(isokmerge(x^e+q, r), acc(, x^e+q, v)), , my(t=polcoef(p, i)); for(k=0, t, self()(r, p, i-1, (k+x*(t-k))*x^i+q, binomial(t, k)*v, e+k))));

for(k=2, n, my(src=Mat(M)); M=Map(); for(i=1, matsize(src)[1], my(p=src[i, 1]); recurse(n-k, p, poldegree(p), 0, src[i, 2], 0)));

a(n)={vecsummy(TournamentsByScoreSeqM=Winners(n, )); sum(i=1, matsize(p, rM)->r>0||[1], if(pollead(pM[i, 1])==1), M[, i, 2]))} \\ Andrew Howroyd, Feb 28 29 2020

EXTENSIONS

a(1)=1 inserted and a(12)-a(15) and beyond from Andrew Howroyd, Feb 28 2020

#12 by Andrew Howroyd at Sat Feb 29 10:14:55 EST 2020
PROG

TournamentsByScoreSeq(n, fokisok)={

my(recurse(r, p, i, q, v, e)=if(i<0, if(fokisok(x^e+q, r), acc(x^e+q, v)), my(t=polcoeffpolcoef(p, i)); for(k=0, t, self()(r, p, i-1, (k+x*(t-k))*x^i+q, binomial(t, k)*v, e+k))));

#11 by Andrew Howroyd at Fri Feb 28 17:13:20 EST 2020
DATA

1, 2, 6, 32, 600, 20544, 1218224, 160241152, 42129744768, 21293228876800, 22220602090444032, 45959959305969143808, 188702851949391611599872, 1566370829898884830446395392, 25801614282517307546368494213120

EXTENSIONS

a(1)=1 inserted and a(12)-a(1415) from Andrew Howroyd, Feb 28 2020

Discussion
Sat Feb 29
03:17
Joerg Arndt: I'd rename "fok" to something else 8^)