2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/64551Cayley's 1875 enumerations of centered and bicentered alkanes (unlabeled trees of valency at most 4) are corrected and extended -- possibly for the first time in 124 years.6 pagesCombinatorics05C05On Cayley's Enumeration of Alkanes (or 4-Valent Trees)text