Number Theory #0: Common Formulae — Legendre's Formula & Divisor Convolutions
Legendre’s formula, divisor and multiple convolutions in O(n log n), offline-difference batch processing for H(n)=Σf(d)g(⌊n/d⌋).
Sieve
Index
All notes
Number Theory #3: From Eratosthenes to Möbius Inclusion-Exclusion
Eratosthenes sieve for μ; g/f/h framework; Conclusions 1 and 2 with derivations and tables; GCD table intuition; CF 803F Coprime Subsequences with bottom-up and Möbius approaches.
Number Theory #3.1: Sieve Problems — Coin System DP via Sieve
Greedy optimality for divisibility-chain coin systems, DP over the maximum denomination, and a sieve-style transition by adding one larger coin.