Numbering of Diodes and Transistors
To give you some hope, the 1N and 2N series refer to the number of junctions in the devices. 







simulate this circuit &ndash; Schematic created using CircuitLab


1N will almost (just covering the exceptions) always mean a diode of some sort as they have only one PN junction. 
2N refers usually to bipolar junction transistors which have two PN junctions.
Here is a 3N187 - a dual insulated-gate field-effect transistor. It has four leads.


A web search found some 4N and 6N but they seem to be opto-couplers and I can't see the continuation of the 1N, 2N pattern.

See stephenvh's answer to Is there any reasoning behind component names? for further information.