%I #10 Feb 07 2020 14:18:01
%S 240,360,480,504,630,672,756,780,900,960,990,1020,1092,1140,1170,1188,
%T 1344,1386,1400,1428,1530,1540,1596,1638,1820,1920,1932,1950,2070,
%U 2112,2240,2244,2268,2376,2380,2448,2496,2508,2610,2652,2660,2688,2736,2800
%N Perimeters of Pythagorean triangles that can be constructed in exactly 4 different ways.
%H Ray Chandler, <a href="/A099833/b099833.txt">Table of n, a(n) for n = 1..10000</a>
%H Ron Knott, <a href="http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Pythag/pythag.html">Pythagorean Triples and Online Calculators</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PythagoreanTriple.html">Pythagorean Triple.</a>
%H <a href="/index/Ps#PyTrip">Index entries related to Pythagorean Triples.</a>
%e a(1)=240 = 15+112+113 = 40+96+104 = 48+90+102 = 60+80+100; a(2)=360 = 36+160+164 = 60+144+156 = 72+135+153 = 90+120+150.
%Y Cf. A098714, A099381, A099382, A156687.
%K nonn
%O 1,1
%A _Hugo Pfoertner_, Oct 27 2004