MathDB

A frog jumps around on the grid points in the plane, from one grid point to another. The frog starts at the point

(0, 0)

. Then it makes, successively, a jump of one step horizontally, a jump of

2

steps vertically, a jump of

3

steps horizontally, a jump of

4

steps vertically, et cetera. Determine all

n > 0

such that the frog can be back in

(0, 0)

after

n

jumps.

Problem Statement