PROOF WITHOUT WORDS: SUMS OF SUMS OF TRIANGULAR NUMBERS. Far East Journal of Mathematical Education, [S. l.], v. 24, p. 5–6, 2022. DOI: 10.17654/0973563123002. Disponível em: https://pphmjopenaccess.com/fejme/article/view/136. Acesso em: 5 jan. 2026.