MathDB

11

Part of 1991 IMO Shortlist

Problems(1)

combinatorial sum

Source: IMO ShortList 1991, Problem 11 (AUS 4)

4/26/2005
Prove that \sum_{k \equal{} 0}^{995} \frac {( \minus{} 1)^k}{1991 \minus{} k} {1991 \minus{} k \choose k} \equal{} \frac {1}{1991}
combinatoricsseries summationbinomial coefficientsSummationCombinatorial IdentityIMO Shortlist