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%I #17 Oct 22 2021 11:33:58
%S 24,120,240,336,840,840,720,1320,2520,2016,3696,2184,5280,5544,6240,
%T 3960,3360,9360,10920,10296,4896,6864,14280,18480,6840,22440,17160,
%U 10920,20064,28560,9240,31824,31920,31416,26520,16320,12144,41496,47880,43680,50160
%N Common differences in triples of squares in arithmetic progression, that are not a multiples of other triples in (A198384, A198385, A198386).
%H Ray Chandler, <a href="/A198438/b198438.txt">Table of n, a(n) for n = 1..10000</a>
%H Keith Conrad, <a href="http://www.math.uconn.edu/~kconrad/blurbs/ugradnumthy/3squarearithprog.pdf">Arithmetic progressions of three squares</a>
%H Reinhard Zumkeller, <a href="/A198435/a198435.txt">Table of initial values</a>
%F a(n) = A198387(A198409(n)) = A198436(n) - A198435(n) = A198437(n) - A198436(n).
%t wmax = 1000;
%t triples[w_] := Reap[Module[{u, v}, For[u = 1, u < w, u++, If[IntegerQ[v = Sqrt[(u^2 + w^2)/2]], Sow[{u^2, v^2, w^2}]]]]][[2]];
%t tt = Flatten[DeleteCases[triples /@ Range[wmax], {}], 2];
%t #[[2]] - #[[1]]& /@ DeleteCases[tt, t_List /; GCD@@t > 1 && MemberQ[tt, t/GCD@@t]] (* _Jean-François Alcover_, Oct 22 2021 *)
%o (Haskell)
%o a198438 n = a198438_list !! (n-1)
%o a198438_list = map a198387 a198409_list
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Oct 25 2011
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