It was narrated from ‘Irbad bin Sariyah that the Messenger of Allah ﷺ used to ask for forgiveness for the first row three times and for the second row twice. (Using translation from Ibn Mājah 996)   

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ «يَسْتَغْفِرُ لِلصَّفِّ الْأَوَّلِ ثَلَاثًا وَللثَّانِي مَرَّةً»  

This tradition has also been narrated on the authority of ‘A’ishah through a different chain. (Using translation from Abū Dāʾūd 99)  

عَنِ النَّبِيِّ ﷺ نَحْوَهُ