You are receiving what is called
clear QAM, the channel numbers will generally be odd like you've found out, nothing you can do to correct this other than to rent a STB or DVR. To make matters worse cable companies like Comcast have a nasty habit of occasionally rearranging the channel numbers requiring a rescan.
Generally at least in my area the locals have the same channel numbers, eg. OTA channel 4.1 will be Comcast 4.1 but other channels aren't so nice and never expect to get the numbers like 242 etc, without anything other than a cable company STB, DVR or Cable Card.
PS, generally it's frowned upon to post the same question in several forums, especially minutes apart
http://www.avsforum.com/t/1452139/channel-codes-for-cable-without-box
http://www.avsforum.com/t/1452142/channels-dont-make-senseEdited by jjeff - 1/15/13 at 3:55pm