מדרש על במדבר 26:35

Our Rabbis were taught: "Seven persons overlined the entire world — namely, Meshushelach saw Adam the first; Shem saw Meshushelach; Jacob saw Shem; Amram saw Jacob; Achiya, the Shilanite, saw Amram; Elijah the Prophet has seen Achiya, and is still alive." But how can you say Achiah saw Amram? Is it not written (Num. 26, 35) There was not left of them one man save Caleb and Joshua? R. Hamnuna said: "The tribe of Levi was excluded from the decree [to die in the desert], as it is written (Ib. 14, 29) In this wilderness shall your carcasses fall, and all that were numbered of you, according to your whole number from twenty years; i.e., only those who were counted from twenty years, but not the tribe of Levi, of which the number was from thirty years." But from any other tribe you say that no one entered into the land of Israel? Behold! Here is a Baraitha that Yair and Machir, the sons of Manasseh, were born in the time of Jacob, and did not die until after the entering into the land of Israel, for it is said (Josh. 7, 5) And the men of Ai smote of them about thirty-six men, and we are taught in a Baraitha: Thirty-six men exactly, so is the opinion of R. Juda. R. Nachman then said to him: "How can you say so? Is it not written about thirtysix. We must therefore say that this refers to Yair b. Manasseh, who equalled the majority of the Sanhedrin." [Hence he entered the land of Israel]. R. Acha b. Jacob said: "Those who were less than twenty and more than sixty years old were not included in that decree."