I have this lens that came with a Ricoh Singlex 35mm film camera I bought very cheap - just to get the Rikenon 1.4. The Singlex will take any Nikon F mount lens, but a Nikon F body will not accept a Rikenon lens .
Rikenon lenses of this style have one attachment ear on the flange that is longer than the other two - so it won't fit. It can be filed or ground down to fit, but I haven't seen one done yet.
I would like to know too !
Very good article here:
The Ricoh that's a Nikon made by Mamiya - Welcome to the Ricoh Singlex
Ricoh developed a bit of a reputation for good SLR bodies and lenses using the M42 & Pentax K Mount. The company still makes K mount dSLR under the Pentax brand. But weirdly their first