Trường Bộ Kinh (Digha Nikaya) 1:236
SUJATOYāvatā, ānanda, ariyaṁ āyatanaṁ yāvatā vaṇippatho idaṁ agganagaraṁ bhavissati pāṭaliputtaṁ puṭabhedanaṁ.
As far as the civilized region extends, as far as the trading zone extends, this will be the chief city: the Pāṭaliputta trade center.