75. Who was Korah's father?

Esau was Korah's father.

This is so important that it is repeated three times in Genesis 36.
And Aholibamah bare Jeush, and Jaalam, and Korah: these are the sons of Esau, which were born unto him in the land of Canaan. Genesis 36:5

And these were the sons of Aholibamah, the daughter of Anah the daughter of Zibeon, Esau's wife: and she bare to Esau Jeush, and Jaalam, and Korah. Genesis 36:14

And these are the sons of Aholibamah Esau's wife; duke Jeush, duke Jaalam, duke Korah: these were the dukes that came of Aholibamah the daughter of Anah, Esau's wife. Genesis 36:18

And 1 Chronicles agrees, saying:
The sons of Esau; Eliphaz, Reuel, and Jeush, and Jaalam, and Korah. 1 Chronicles 1:35

Eliphaz was Korah's father.

Genesis 36 also says that Eliphaz was Korah's father.
These were dukes of the sons of Esau: the sons of Eliphaz the firstborn son of Esau; duke Teman, duke Omar, duke Zepho, duke Kenaz, Duke Korah, duke Gatam, and duke Amalek: these are the dukes that came of Eliphaz in the land of Edom; these were the sons of Adah. Genesis 36:15-16

To avoid the contradiction, apologists claim that there were two Korahs, one a son and the other a grandson of Esau.

But doesn't work since since Korah is not included among the sons of Eliphaz listed in 1 Chronicles.

The sons of Eliphaz; Teman, and Omar, Zephi, and Gatam, Kenaz, and Timna, and Amalek. 1 Chronicles 1:36