Probably refers to Āsīvisa Sutta (S.iv.172), but may be (2).
It was taught by Majjhantika Thera to the Nāga-king Aravāla and the people of Kasmīra and Gandhāra.
Eighty thousand of the listeners accepted the new religion and one hundred thousand were ordained after the discourse (Sp.i.66; Mhv.xii.26).
It was also taught by Mahinda in Sri Lanka in the Nandanavana at Anurādhapura on the third day after his entry into the city. Thirty thousand people were converted. Ibid., xv.178‑9; Sp.i.80; Mbv.133.