lean_workbook_plus_39819

Define a function f : N to N\*N as follows: $f(1) = (1,1)$ $f(2) = (2,1)$ $f(3) = (1,2)$ $f(4) = (3,1)$ $f(5) = (2,2)$ $f(6) = (1,3)$ $f(7) = (4,1)$ and continue moving in a triangular pattern.