Good call, now I'm embarrassed. I should've known that. Funny how the mind works. I knew he died in his 50's and was involved in the Manhattan project but somehow was content lumping him in with all the other scientists from Operation Paperclip and using loose math that 1981 was possible.
John von Neumann died in 1957. The name is a bit generic, so many results show up. Hence I wished there was a way to limit search to a range of years.