It was narrated from Kathir bin ‘Abdullah, from his father, from his grandfather, that the Messenger of Allah (ﷺ) said the Takbir five times.
Sunan Ibn Majah Book 6, Hadith 74
← Previous Hadith “Zaid bin Arqan used to say the Takbir four times in the funeral prayer, and he said the Takbir five times for one funeral. I asked him (about that) and he said: ‘The Messenger of Allah (ﷺ) used to do that.’”

Sunan Ibn Majah Book 6, Hadith 73 Next Hadith → “I heard the Messenger of Allah (ﷺ) say: ‘The (funeral) prayer should be offered for a child.’”

Sunan Ibn Majah Book 6, Hadith 75