I've got a list of hundreds of page requests from the same IP and I need to know if these could be requests by different computers.
There is no limit to the number of computers, however there is a limit to the number of simultaneous connections because of the possibility of ephemeral port exhaustion. More computers usually means more connections so there is a practical limit to how many computers will typically share the same IP address. Usually with a very large number of computers, multiple IP addresses will be shared in a pool to be used for NAT.
As many as can dance on the head of a pin - Or more accurately as many as an administrator wants to hide behind NAT.
Besides NAT, they could be behind a proxy. if the proxy is nice to you, you might find more informations in the HTTP-Headers of the requests. Look for X-Forwarded-For headers, which might help you to get closer to your real usercount.
There can be any number of computers on a LAN (It may depend on the physical medium used between them i.e. cables, repeaters etc.), normally there is a single Gateway (at least one is required) to connect to the Internet. These Gateways normally have multiple IPs (both private and public) for the communication.
Now as the LAN can inturn be set of LANs... figuring out the correct client is a herculean task if not impossible... Though you can still get to that by looking to the routing tables of Gateway or by accessing NAT...This Link may help
Most of the times public IP is used by ISPs and Large or Mid size Organizations... That is why using client IP is not considered a wise idea now a days.