ἑξηκοντάκις
From LSJ
βωμὸν Ἀριστοτέλης ἱδρύσατο τόνδε Πλάτωνος, ἀνδρὸς ὃν οὐδ' αἰνεῖν τοῖσι κακοῖσι θέμις → Aristotle had this altar of Plato set up — Plato, a man whom the wicked dare not even mention in praise
English (LSJ)
poet. ἑξηκοντάκι, Adv. sixty times, Pi. O. 13.99.
Greek (Liddell-Scott)
ἑξηκοντάκις: ᾰ, καὶ ποιητ. -άκι, Ἐπίρρ., ἑξήκοντα φοράς, Πίνδ. Ο. 13. 141.