On Sun, Jun 12, 2022 at 3:06 AM Ali Sada via SeqFan <seqfan at list.seqfan.eu> wrote: > a(n) = ((c^4-a^4-b^4)/288)^1/2, where a, b, and c are the Pythagorean > triples ordered by increasing c. > You need to specify how to order triples with the same c, like (20, 15, 25) and (24, 7, 25).