Gryszka, K. 2023. The identity 7^(3n)+7^(3n+1)=(2∙7^n )^3 and its generalizations. Annales Universitatis Paedagogicae Cracoviensis | Studia ad Didacticam Mathematicae Pertinentia. 15, (Dec. 2023), 5–13. DOI:https://doi.org/10.24917/20809751.15.1.