Is it permissible to offer an Uḍḥiyah (sacrificial animal) on behalf of a newborn some time after their birth, and what are the recommended specifications for this sacrifice?

The aqiqah is a confirmed Sunnah for those who are able, consisting of slaughtering two sheep for a male and one sheep for a female. If a person was in hardship at the time of the child's birth and then his affairs became easy, it is sunnah for him to perform the aqiqah for his child, based on the Prophet's (peace be upon him) saying: "Every child is mortgaged by his aqiqah."