It is narrated from Sayyiduna Amr bin al-As (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) taught him fifteen prostrations in the Qur'an: "Three of them are in the Mufassal surahs, and in Surah al-Hajj there are two prostrations."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3708