In an article by George Johnson in the New York Times back in 1999, it says that an amateur mathematician from India once sent Ian Stewart a proof of the Ramanujan-Nagell theorem that the Diophantine equation $x^2 + 7 = 2^n$ is solvable if and only if $n = 3, 4, 5, 7, 15$. The proof "was badly typed on strange paper and cast in an idiosyncratic style that would have given any journal editor the impression that the writer was a crank." However, it was correct, and after getting some help cleaning it up, the man published the proof.

To me, this is an inspiring story, and I would like to know the name of this man and to see the paper. I asked Ian Stewart but he said that he remembers the incident but not the identity of the man in question. I would try asking George Johnson but I am not sure how to contact him. I searched MathSciNet but was not able to guess which paper it was.

Does anyone know more details?

Mathematical Cranksdoes not contain the word "Nagell" (according to amazon's search inside the book), so I'm afraid the answer is not there. – John Stillwell Jun 5 '10 at 7:24