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We use the multifractal detrended fluctuation analysis (MF-DFA), to study the sunspot number fluctuations. We show that sunspot time series has a crossover time scale $(s_{\times})$, where the signal has different correlation exponents in time scales $s > s_{\times}$ and $s < s_{\times}$. Comparing the MF-DFA results of the original time series to those for shuffled and surrogate series, we conclude that its multifractality nature is almost due to long-range correlations.
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