3

Part of 2009 Federal Competition For Advanced Students, P1

Problems(1)

n bus stops placed around a circular lake, no of bus routes

Source: Austrian Federal Competition For Advanced Students 2009, Part 1, p3

n

bus stops placed around the circular lake. Each bus stop is connected by a road to the two adjacent stops (we call a segment the entire road between two stops). Determine the number of bus routes that start and end in the fixed bus stop A, pass through each bus stop at least once and travel through exactly

n+1