Sayyiduna Buraydah (may Allah be pleased with him) narrates this saying of the Prophet (peace and blessings be upon him): "The aqiqah (animal) should be slaughtered on the seventh day, or on the fourteenth day, or on the twenty-first day."
Al-Tabarani recorded it in al-Saghir and al-Awsat; its chain contains Isma'il bin Muslim al-Makki, who is da'if (weak) because of his many errors and misconceptions.
Sayyiduna Anas (may Allah be pleased with him) narrates: the Prophet (peace and blessings be upon him) performed his own aqiqah after he had been sent as a Prophet.
Al-Bazzar and al-Tabarani in al-Awsat recorded it. Al-Tabarani's narrators are the narrators of the Sahih, except for al-Haytham bin Jamil, and he is thiqah (trustworthy). Al-Tabarani's teacher Ahmad bin Mas'ud al-Khayyat al-Maqdisi is not mentioned in "al-Mizan".