Grasshopper on the Number Line

A grasshopper sits at 0 0 on the integer number line and repeatedly jumps to the right, each jump covering 1 1 unit or 2 2 units with probability 12 \tfrac{1}{2} each, independently forever. For a positive integer k k , let pk p_k denote the probability that the grasshopper ever touches down exactly on k k . Which k>0 k > 0 maximizes pk p_k , and what is that maximum probability?

Answer

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