The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A059082

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A059082

Number of 6-element T_0-antichains on a labeled n-set, n = 0, ..., 64.
(history; published version)

#15 by Alois P. Heinz at Mon Sep 04 18:05:06 EDT 2017

STATUS

editing

approved

#14 by Alois P. Heinz at Mon Sep 04 18:04:56 EDT 2017

CROSSREFS

Cf. A059079-, A059080, A059081, A059083, A059048-, A059049, A059050, A059051, A059052.

#13 by Alois P. Heinz at Mon Sep 04 18:03:25 EDT 2017

DATA

0, 0, 0, 0, 1, 1370, 738842, 176796382, 26021566536, 2807549333568, 245222809302240, 18418417704308160, 1236761946163054080, 76210520306627266560, 4388527139331858082560, 239214759548062858560000, 12457699161320493400320000, 623967599346727576292352000

#12 by Alois P. Heinz at Mon Sep 04 18:02:31 EDT 2017

LINKS

Alois P. Heinz, <a href="/A059082/b059082.txt">Table of n, a(n) for n = 0..64</a>

KEYWORD

nonn,easy,fini,nonn,full,changed

STATUS

proposed

editing

#11 by Jon E. Schoenfield at Mon Sep 04 17:30:08 EDT 2017

STATUS

editing

proposed

Discussion

Mon Sep 04

17:59

Alois P. Heinz: a(n) will be 0 for n>=65 as it is for n<=3. Perhaps the b-file should take all the non-zero values and keyword:full given.

#10 by Jon E. Schoenfield at Mon Sep 04 17:30:05 EDT 2017

NAME

Number of 6-element T_0-antichains on a labeled n-set, n = 0, ..., 64.

MAPLE

f:=proc(k, n) if k+1<=n then RETURN(0) else RETURN(k!/(k - n)!) fi: end; a:=n->(1/6!)*(f(64, n) - 30*f(48, n) + 120*f(40, n) + 60*f(36, n) + 60*f(34, n)- 12*f(33, n) - 345*f(32, n) - 720*f(30, n) + 810*f(28, n) + 120*f(27, n) + 480*f(26, n) + 360*f(25, n) - 480*f(24, n) - 720*f(23, n) - 240*f(22, n) - 540*f(21, n) + 1380*f(20, n) + 750*f(19, n) + 60*f(18, n) - 210*f(17, n) - 1535*f(16, n) - 1820*f(15, n) + 2250*f(14, n) + 1800*f(13, n) - 2820*f(12, n) + 300*f(11, n) + 2040*f(10, n) + 340*f(9, n) - 1815*f(8, n) + 510*f(7, n) - 1350*f(6, n) + 1350*f(5, n) + 274*f(4, n) - 548*f(3, n) + 120*f(2, n)); seq(a(n), n=0..20); (# Pab Ter (pabrlos2(AT)yahoo.com), Nov 06 2005

STATUS

approved

editing

#9 by R. J. Mathar at Thu Jun 13 14:49:55 EDT 2013

STATUS

editing

approved

#8 by R. J. Mathar at Thu Jun 13 14:49:50 EDT 2013

AUTHOR

_Vladeta Jovovic, _, Goran Kilibarda (vladeta(AT)eunet.rs), , Jan 06 2001

STATUS

approved

editing

#7 by N. J. A. Sloane at Thu Nov 11 07:34:06 EST 2010

LINKS

V. Jovovic, <a href="a59083/A059083/a059083.pdf">Formula for the number of m-element T_0-antichains on a labeled n-set</a>

KEYWORD

easy,fini,nonn,new

#6 by N. J. A. Sloane at Tue Jun 01 03:00:00 EDT 2010

KEYWORD

easy,fini,nonn,new

AUTHOR

Vladeta Jovovic, Goran Kilibarda (vladeta(AT)Euneteunet.yurs), Jan 06 2001