This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A120213 #7 Dec 29 2023 12:44:34 %S A120213 4,12,12,15,15,16,20,20,21,24,24,28,28,32,33,35,36,36,39,40,40,44,44, %T A120213 45,48,48,51,52,52,55,56,56,57,60,60,60,60,63,64,65,68,68,69,72,72,75, %U A120213 76,76,77,77 %N A120213 "a" values providing solution x != b in A120211, i.e., in y^2 = x*(a^2 - x)*(b^2 + x) with a, b legs in primitive Pythagorean triads. %e A120213 Primitive Pythagorean triad: 4, 3, 5. %e A120213 Weierstrass equation: y^2 = x*(4^2 - x)*(3^2 + x). %e A120213 Smallest integer solution: (x, y) = (6,30). %e A120213 As x != b, a = 4 is in the sequence. %Y A120213 Cf. A120210, A120211, A120212. %K A120213 nonn %O A120213 0,1 %A A120213 _Giorgio Balzarotti_, _Paolo P. Lava_, Jun 10 2006