'Seventy seven' in the Bible

If Cain is to be avenged seven times as much, then Lamech seventy-seven times!"

And all the days of Lemech were seven hundred and seventy-seven years; and he died.

And he caught a young man of Succoth, and questioned him; and he wrote down for him the officials and elders of Succoth, seventy-seven men.

The children of those that had been carried away, who had come out of the captivity, presented burnt-offerings to the God of Israel, twelve bullocks for all Israel, ninety-six rams, seventy-seven lambs, twelve he-goats for a sin-offering: all for a burnt-offering to Jehovah.