High Quality Content by WIKIPEDIA articles! Sociable numbers are generalizations of the concepts of amicable numbers and perfect numbers. A set of sociable numbers is a kind of aliquot sequence, or a sequence of numbers each of whose numbers is the sum of the factors of the preceding number, excluding the preceding number itself. For the sequence to be sociable, the sequence must be cyclic, eventually returning to its starting point. The period of the sequence, or order of the set of sociable numbers, is the number of numbers in this cycle.