802.11 Channel Use Regs
If your equipment supports it, you can set it to Channel 155, however, this is not desirable, as you will get interference from the two adjacent channels. The recommendations are just that, recommendations. There are no requirements in FCC 15.245 or 15.247 (ISM regulations) for a specific channel, as long as you are not near the band's edge.

Edit: 
Following Dave's comment: There are the U-NII (15.407) rules which differ slightly from the 15.247 rules, but there is no specific channel requirements. If the equipment supports it, any frequency inside the band can be used. 
As for narrow band FHSS transmissions, there is a different set of requirements which applies to them.