MathDB

Number of connected subsets of {1,2, ... ,10}

Source: Pan African Olympiad 2008

October 1, 2011

combinatorics proposedcombinatorics

Problem Statement

A set of positive integers

X

is called connected if

|X|\ge 2

and there exist two distinct elements

m

and

n

X

such that

m

is a divisor of

n

. Determine the number of connected subsets of the set

\{1,2,\ldots,10\}