Indian Mathematical Olympiad 1988 - Problem 1
Source:
August 14, 2009
number theory proposednumber theory
Problem Statement
Let be a rearrangement of the numbers . Suppose that is odd. Prove that the product
\left(m_1\minus{}1\right)\left(m_2\minus{}2\right)\cdots \left(m_n\minus{}n\right)
is an even integer.