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 A239744 #24 Feb 16 2025 08:33:21 %S A239744 2,63,1034,14474,185864,2269788,26809924,309224756,3503496007, %T A239744 39147452729,432599522197 %N A239744 Number of Pythagorean triangles (x, y, z) with legs x < y <= 10^n. %C A239744 A Pythagorean triangle is a right triangle with integer side lengths x, y, z forming a Pythagorean triple (x, y, z). %C A239744 Because (x, y, z) is equivalent to (y, x, z), the total number of Pythagorean triangles with legs x, y < 10^n is b(n) = 2*a(n) = 4, 126, 2068, 28948, 371728, ... %H A239744 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PythagoreanTriangle.html">Pythagorean Triangle</a>. %H A239744 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PythagoreanTriple.html">Pythagorean Triple</a>. %e A239744 a(1) = 2, because the only two Pythagorean triangles with x < y < 10 are [3, 4, 5] and [6, 8, 10]. %Y A239744 Cf. A008846, A020882, A020883, A020884, A046086, A046087, A101931, A101929, A239581, A239786. %K A239744 nonn,more %O A239744 1,1 %A A239744 _Martin Renner_, Mar 26 2014 %E A239744 a(6)-a(11) from _Giovanni Resta_, Mar 27 2014