Musannaf Ibn Abi Shayba 3:5314

Muhammad ibn Fudayl narrated to us, from Wiqa’, who said: Sa’id ibn Jubayr used to lead us in prayer during Ramadan. He would pray twenty nights with us, performing six tarwihat. When the last ten nights arrived, he would seclude himself (i’tikaf) in the mosque and pray seven tarwihat with us.