Code availability

The supplementary Python scripts derive_exchange.py and generate_figures.py regenerate the numerical exchange-counting tables, signed-threshold table, exchange-coefficient checks, and manuscript figures. The scripts use only explicitly stated shell degeneracies, same-spin pair-count equations, Slater-Condon angular-coefficient algebra, and fixed illustrative constants reported in the manuscript. No adopted configuration-label table is read to generate the exchange-counting results.

The package is provided for peer-review reproducibility of the Madelung anomaly ladder paper.
