Genesis 10:2 (NKJV)
The sons of Japheth were Gomer, Magog, Madai, Javan, Tubal, Meshech, and Tiras.
v6) The sons of Ham were Cush, Mizraim, Put, and Canaan.
v22) The sons of Shem were Elam, Asshur, Arphaxad, Lud, and Aram.
In this passage, Shem whose God is the LORD (Yahweh) has Five sons.
Japheth who will be enlarged by God has Seven sons
Ham who is the younger son in Gen 9:24 (where younger is the hebrew word "qaton" meaning insignificant) ends up having Four sons.
I wonder if the difference in their number of sons is related to Noah's prophecy in Gen 9:25-27.