Kami Ni Homura Wo - Saishuu Teiri No Shoumei Houhou summary:

Fermat's Last Theorem. It is the greatest problem in mathematics, and has fascinated mathematicians all over the world for 350 years. In 1951, in postwar Japan, a young mathematician took on the challenge of the "Devil's Proof." His name was Andy Homura. His life and the history of the mathematics world were set in motion by the appearance of a great genius, a young girl named Lama. The proof that Homura bet her entire life on begins.