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 A376209 #9 Sep 22 2024 15:48:35 %S A376209 16,21,36,46,51,55,66,76,91,94,111,121,123,126,136,157,171,172,181, %T A376209 186,196,211,216,225,237,241,246,268,276,286,289,291,297,301,310,315, %U A376209 331,336,346,351,354,361,366,378,384,396,412,421,436,441,442,445,456,463,466 %N A376209 Numbers k for which the hypotenuse z=4*k+1 occurs in more than one primitive Pythagorean triangle, such that 2 distinct triangles (x1,y1,z), (x2,y2,z) with opposite parity of their short legs x1 and x2 exist (xi < yi < z). %H A376209 Hugo Pfoertner, <a href="/A376209/b376209.txt">Table of n, a(n) for n = 1..10000</a> %e A376209 See A376210. %o A376209 (PARI) \\ Uses function is_a376208 from A376208 %o A376209 is(n) = is_a376208(n,0) && is_a376208(n,1) %Y A376209 Intersection of A375750 and A376208. %Y A376209 Cf. A376210, A376211. %K A376209 nonn %O A376209 1,1 %A A376209 _Hugo Pfoertner_, Sep 21 2024