NoAge. The Professor's Favorite Equation

The mathematics professor lives in a world of numbers. After an injury, his brain retains memories for only eighty minutes; he remembers neither dates, nor names, nor love, nor friendship — nothing but factorials, prime numbers, and equations.
The housekeeper, who... takes care of him, is far from mathematics, but the Professor reveals to her and her son a secret world of numbers, where simple and understandable quantities are comparable to the scales of the Universe.
Each morning they get to know each other again. Their day is filled with everyday life, mathematics, baseball, and love.
A novel by Yoko Ogawa, one of the most renowned contemporary Japanese writers, about memory, what it means to live in the present, and the mysterious equations that can connect people.