Bad problem
Source: China South East Mathematical Olympiad 2016 Grade 10 Prob. 6
July 31, 2016
combinatorics
Problem Statement
Toss the coin times, assume that each time, only appear only head or tail
Let denote number of way that head appear in multiple of times among times
Let denote numbe of way that head appear in multiple of times among times
Find and
Find the number of positive integer that