(17!/(18-k)!)/(k-1)!+(15!/(16-k)!)/(k-1)!+(13!/(14-k)!)/(k-1)!+(11!/(12-k)!)/(k-1)!+(9!/(10-k)!)/(k-1)!+(7!/(8-k)!)/(k-1)!+(6!/(7-k)!)/(k-1)!+(5!/(6-k)!)/(k-1)!+(4!/(5-k)!)/(k-1)!,k=15