MathDB
2021 Team P8

Source:

March 2, 2021
algebranumber theory

Problem Statement

Determine the number of functions ff from the integers to {1,2,,15}\{1,2,\cdots,15\} which satisfy f(x)=f(x+15)f(x)=f(x+15) and f(x+f(y))=f(xf(y))f(x+f(y))=f(x-f(y)) for all x,yx,y.
Proposed by Vijay Srinivasan