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 A383413 #17 May 10 2025 11:58:35
%S A383413 6,24,30,36,42,54,60,66,72,84,90,96,114,120,126,132,144,150,156,168,
%T A383413 180,198,204,210,216,234,240,252,264,270,288,294,300,306,324,330,336,
%U A383413 360,378,384,390,396,408,420,456,462,468,480,486,504,510,522,528,540,546,576,594
%N A383413 Area A of triangles such that the sides are distinct integers and A is an integer.
%C A383413 All terms are multiples of 6.
%C A383413 Subsequence of A188158.
%H A383413 Wikipedia, <a href="https://en.wikipedia.org/wiki/Heronian_triangle">Heronian triangle</a>
%e A383413 72 is in the sequence because the triangle with sides {a=5, b=29, c=30} has an area of exactly 72 and all sides are distinct.
%e A383413 12 is not in the sequence because this area is only possible with the isosceles triangles {a=5, b=5, c=6} and {a=5, b=5, c=8} with a and b not distinct.
%t A383413 nn = 450; lst = {}; Do[s = (a + b + c)/2; If[IntegerQ[s], area2 = s (s - a) (s - b) (s - c); If[a!=b!=c&&0 < area2 <= nn^2 && IntegerQ[Sqrt[area2]], AppendTo[lst, Sqrt[area2]]]], {a, nn}, {b, a-1}, {c, b-1}]; Union[lst]; lst (* _James C. McMahon_, May 10 2025 *)
%Y A383413 Cf. A188158, A316853.
%K A383413 nonn
%O A383413 1,1
%A A383413 _Karl-Heinz Hofmann_, Apr 26 2025