I suck at regex

Right. I'm trying to ban certain IP ranges via a rewrite rule in .htaccess.

If I want to ban 123.123.0.0 to 123.128.255.255 I enter
123\.(12[3-8]) which works fine.

However, I'm having trouble with ranges such as 123.123.0.0 to 123.138.255.255. In this example, I use two expressions:
123\.(12[3-9])  Covers 123.123 through 123.129
123\.(13[0-8])  Covers 123.130 through 123.138

Is it possible to combine these two expressions into a single one?
Danke.

123\.[(12[3-9])(13[0-8])], dude.