Salim (may Allah have mercy on him) narrates from his father (Sayyiduna Abdullah bin Umar, may Allah be pleased with them both) that a man saw Laylat al-Qadr on the twenty-seventh night, so the Messenger of Allah (peace and blessings be upon him) said: "Your dream is in the last ten (nights), so seek it in the odd nights of them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8530