CNCM Online R1P1
Source:
September 2, 2020
Problem Statement
Pooki Sooki has hoodies, and he may wear any of them throughout a 7 day week. He changes his hoodie exactly times during the week, and will only do so at one of the midnights. Once he changes out of a hoodie, he never wears it for the rest of the week. The number of ways he can wear his hoodies throughout the week can be expressed as . Find .
Proposed by Minseok Eli Park (wolfpack)