Musannaf Ibn Abi Shayba 1:273

Abu al-Ahwas narrated to us, from Mansur, from Hilal ibn Yasaf, from Salamah ibn Qays, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "When you perform wudu, then rinse your nose (istanthir), and when you clean yourself with stones (istajmart), then use an odd number."