Some men amongst the companions of the Prophet ﷺ were shown in their dreams that the night of Qadr was in the last seven nights of Ramadan. Messenger of Allah ﷺ said, "It seems that all your dreams agree that (the Night of Qadr) is in the last seven nights, and whoever wants to search for it (i.e. the Night of Qadr) should search in the last seven (nights of Ramadan). (Using translation from Bukhārī 2015)  

أَنَّ رِجَالًا مِنْ أَصْحَابِ النَّبِيِّ ﷺ أُرُوا لَيْلَةَ الْقَدْرِ فِي الْمَنَامِ فِي السَّبْعِ الْأَوَاخِرِ فَقَالَ رَسُولُ اللهِ ﷺ «إِنِّي أَرَى رُؤْيَاكُمْ قَدْ تَوَاطَأَتْ فِي السَّبْعِ الْأَوَاخِرِ فَمَنْ كَانَ مُتَحَرِّيَهَا فَلْيَتَحَرَّاهَا فِي السَّبْعِ الْأَوَاخِر»