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A192102 Number of distinct (unordered) pairs of partitions of a 9-element set that have Rand distance n. 3
31572, 141624, 452508, 1341648, 3266172, 7234374, 12259368, 18992502, 23324140, 28129626, 26605908, 26190612, 21568932, 17119818, 13040280, 8948079, 6244308, 3679032, 2431044, 1250109, 640908, 315828, 197568, 57288, 46116, 30366, 25732, 7695, 4104, 2226, 3780, 2205, 1344, 378, 36, 1 (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..36.

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 for set size 8.

Sequence in context: A321054 A234205 A236136 * A322123 A236062 A187728

Adjacent sequences:  A192099 A192100 A192101 * A192103 A192104 A192105

KEYWORD

nonn,fini,full

AUTHOR

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

STATUS

approved

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Last modified November 30 08:19 EST 2021. Contains 349419 sequences. (Running on oeis4.)