2 Samuel 18

18:18  Now Absalom in his lifetime had taken and reared up for himself a pillar, which is in the king's dale: for he said, I have no son to keep my name in remembrance: and he called the pillar after his own name: and it is called unto this day, Absalom's place.

I have no son

The pillar mentioned must have been reared before the birth of sons to Absalom. Cf. 2 Samuel 14:27 . Another view is that his sons died in youth. They are not mentioned in the genealogies.