Declension table of ?pattavya

Neuter	Singular	Dual	Plural
Nominative	pattavyam	pattavye	pattavyāni
Vocative	pattavya	pattavye	pattavyāni
Accusative	pattavyam	pattavye	pattavyāni
Instrumental	pattavyena	pattavyābhyām	pattavyaiḥ
Dative	pattavyāya	pattavyābhyām	pattavyebhyaḥ
Ablative	pattavyāt	pattavyābhyām	pattavyebhyaḥ
Genitive	pattavyasya	pattavyayoḥ	pattavyānām
Locative	pattavye	pattavyayoḥ	pattavyeṣu

Compound pattavya -

Adverb -pattavyam -pattavyāt