  Random walks on discrete lattices are fundamental models that form the basis
for our understanding of transport and diffusion processes. For a single random
walker on complex networks, many properties such as the mean first passage time
and cover time are known. However, many recent applications such as search
engines and recommender systems involve multiple random walkers on complex
networks. In this work, based on numerical simulations, we show that the
fraction of nodes of scale-free network not visited by $W$ random walkers in
time $t$ has a stretched exponential form independent of the details of the
network and number of walkers. This leads to a power-law relation between nodes
not visited by $W$ walkers and by one walker within time $t$. The problem of
finding the distinct nodes visited by $W$ walkers, effectively, can be reduced
to that of a single walker. The robustness of the results is demonstrated by
verifying them on four different real-world networks that approximately display
scale-free structure.
