MathDB
2013 General Problem 22

Source:

February 4, 2013

Problem Statement

The set A={1,2,3,,10}A=\{1,2,3,\cdots, 10\} contains the numbers 11 through 1010. A subset of AA of size nn is competent if it contains nn as an element. A subset of AA is minimally competent if it itself is competent, but none of its proper subsets are. Find the total number of minimally competent subsets of AA.