a1 Department of applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel
Abstract
Given a set consisting of n1, objects of type 1, n2 of type 2, …, nk of type k, we denote by
the number of possible derangements of the set i.e. permutations in which no object occupies a site originally occupied by an object of the same type. A formula is found for
in terms of Laguerre polynomials, and some of its implications are considered.
(Received December 04 1974)