This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

Abijam was Asa's father.

1 Kings 15:8 View context

And Abijam slept with his fathers; and they buried him in the city of David: and Asa his son reigned in his stead.

Abijam was Asa's brother. (They both had the same mother, Maachah.)

1 Kings 15:1-2 View context

Now in the eighteenth year of king Jeroboam the son of Nebat reigned Abijam over Judah.

Three years reigned he in Jerusalem. And his mother's name [was] Maachah, the daughter of Abishalom.