2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76590A number $n$ is said to be economical if the prime power factorisation of $n$ can be written with no more digits than $n$ itself. We show that under a plausible hypothesis, related to the twin prime conjecture, there are arbitrarily long sequences of consecutive economial numbers, and exhibit such a sequence of length 9.6 pagesNumber Theory11A63 (Primary); 11A25,11A51 (Secondary)text