Narrated Ibn `Abbās [رضي الله عنه]: The Prophet [ﷺ] said:

❝Look for the night of Qadr in the last ten nights of Ramadān; on the night when nine or seven or five nights remain out of the last ten nights of Ramadān [i.e., 21, 23, 25, 27, 29 respectively].❞

[Sahīh Bukhari, (No. 2021) | Translated By Dr. Muhammad Muhsin Khan]