Pāṇini sūtras

The augment n is added before the Genitive Pl. ending ām, after stems ending in a short vowel, after stems called Nadû (I.4.3 &c), and after the stems ending in the Feminine affix ā

1. hrasva+nadī+āpaḥह्रस्व+नदी+आपः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   hह्	hrasvaह्रस्व	hrasvaह्रस्व	short	hrasvह्रस्व् + plus aअ
   nन्	nadīनदी	nadīनदी	nadīनदी	nadनद् + plus īई
   āआ	āpआप्	āpaḥआपः	āpआप्	āpआप् + plus aḥअः

2. nuṭनुट्

   Part	Lexeme	Sandhi form	Meaning	Stem
   nन्	nuṭनुट्	nuṭनुट्	nuṭनुट्	nuṭनुट्

Anuvṛtti

1. āmiआमि 7·1·52

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   āआ	āmआम्	āmiआमि	āmआम्	āmआम् + plus iइ