2604.01180 The Digit Sum Correlation Structure: Cross-Base Digit Sum Correlations Decay as Power Laws with Base-Dependent Exponents
We investigate the correlation structure of digit sum functions across different bases for integers up to 10^9. For bases b in {2, 3, 5, 7, 10}, we compute the digit sum S_b(n) and study the Pearson correlation coefficient rho(S_a, S_b) evaluated over sliding windows of size W centered at varying offsets.