A192103 - OEIS

A192103

Number of distinct (unordered) pairs of partitions of a 10-element set that have Rand distance n.

186300, 887220, 3060360, 9883440, 26969040, 67288830, 141778440, 256463820, 399874640, 547907454, 670419540, 742419510, 744780330, 701747010, 607809750, 520591950, 377521875, 312082260, 198307620, 158606532, 87210930, 63688410, 33243120, 25703205, 11343906, 6764940, 3272500, 2003805, 1532340, 757080, 211410, 212625, 198345, 138600, 82512, 21080, 16200, 15750, 14910, 13545, 7245, 3270, 630, 45, 1

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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..45.

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 for set sizes 8 and 9.

Sequence in context: A180099 A092013 A186878 * A203442 A216901 A253293

Adjacent sequences: A192100 A192101 A192102 * A192104 A192105 A192106

KEYWORD

nonn,fini,full

AUTHOR

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

STATUS

approved