A192104 Number of distinct (unordered) pairs of partitions of an 11-element set that have Rand distance n.

1163085, 5835060, 21482340, 74471760, 222185304, 612903720, 1469224350, 3164268690, 5762811670, 9538994388, 13513772745, 18112131840, 20675910420, 23653643310, 22677991578, 22923998460, 19287053775, 17554312490, 13495597225, 11143736604, 8029798920, 6035010960, 4254456690, 2872892550, 1924619235, 1215058680, 789847190

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..27.

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, A192102 and A192103 for set sizes 8..10.

Sequence in context: A084554 A339982 A234554 * A210181 A204307 A233664

Adjacent sequences: A192101 A192102 A192103 * A192105 A192106 A192107

Keyword

nonn,fini

Author

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

Status

approved