If everyone needs access to the full version of Crystal instead of just to a viewer, you would need 40 licenses. The desktop version of Crystal is licensed on a named user basis.
You can also write a viewer application - Windows or web - using either Crystal for Visual Studio (.NET) or Crystal for Eclipse (Java). For licensing, you would need to have one copy of Crystal Reports. However, there is a limitation of 5 concurrent sessions and 100 concurrent print jobs if you go this route. It's likely that any 3rd-party viewer app that you purchase would have this same limitation.
I'm not sure how that limitation would work on a Terminal Server, though. If you need to have more than 5 concurrent users, you should look at SAP Crystal Reports Server to serve up reports.
Crystal for Eclipse wiki: https://wiki.scn.sap.com/wiki/display/BOBJ/SAP+Crystal+Reports+version+for+Eclipse+-+Downloads
"Print Job" definition: https://blogs.sap.com/2022/06/03/what-is-a-crystal-print-job/
Do you need the users to just use (run/preview/print/export) the reports (as opposed to design reports)?
If so, yopu could use one of the free/inexpensive 3rd-party Crystal Reports Viewers listed here.