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A192105 Number of distinct (unordered) pairs of partitions of a 12-element set that have Rand distance n. 0
7654350, 40209840, 156637140, 576841320, 1851589872, 5544758076, 14686598520, 35723706480, 75818872580, 144536922420, 242305860072, 370664737190, 506699655660, 643405035240, 746030515164, 812426918688, 833352979140, 795923308950, 741556189440, 644098507272, 547387431756, 444670121610, 349922192400, 268690544925, 197063378424, 147497181678, 99290917440, 73672276095, 45746253960, 32550841950, 19313040780 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The Rand distance of a pair of set partitions is the number of unordered pairs {x; y} such that there is a block in one partition containing both x and y, but x and y are in different blocks in the other partition.

LINKS

Table of n, a(n) for n=1..31.

F. Ruskey and J. Woodcock, The Rand and block distances of pairs of set partitions, Combinatorial algorithms, 287-299, Lecture Notes in Comput. Sci., 7056, Springer, Heidelberg, 2011.

CROSSREFS

Cf. A192100 for set sizes 2..7. A192098 and A192102-A192104 for set sizes 8..11.

Sequence in context: A204803 A187962 A080340 * A233597 A258954 A273101

Adjacent sequences:  A192102 A192103 A192104 * A192106 A192107 A192108

KEYWORD

nonn,fini

AUTHOR

Frank Ruskey and Yuji Yamauchi (eugene.uti(AT)gmail.com), Aug 08 2011

STATUS

approved

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Last modified September 25 18:27 EDT 2022. Contains 356986 sequences. (Running on oeis4.)