I am french My studies : ENS Sèvres (France) and agrégation. Profession : Teacher, retired since 2010. I am currently studying the properties of the congruent numbers. In https://oeis.org/A016090 , The number 16 is OK but 6 Instead of 16 seams better. Is it a lack of attention or an awkwardness? I did not find any other way to communicate.