Custom oid counter

Gents,

Can you please explain, what does mean this expression:

oid="((.1.3.6.1.4.1.789.1.5.4.1.16<32) | (.1.3.6.1.4.1.789.1.5.4.1.17:4294967295))*1024"

What do mean operations:
"<32"
"|"
":4294967295" -- divide by 4Mb ?

Where to see all possible math operations for oids ?

Sorry if my question is silly )

Thanks