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Least even leg of primitive Pythagorean triangles with odd leg 2n+1.
12

%I #10 Mar 05 2020 08:21:38

%S 4,12,24,40,60,84,8,144,180,20,264,312,364,420,480,56,12,684,80,840,

%T 924,28,1104,1200,140,1404,48,176,1740,1860,16,72,2244,260,2520,2664,

%U 308,36,3120,3280,3444,132,416,3960,60,476,168,4704,20,5100,5304,88,5724,5940

%N Least even leg of primitive Pythagorean triangles with odd leg 2n+1.

%C a(n) shares identical entries with A046092(n) except for n=(A081934 - 1)/2.

%H Jean-François Alcover, <a href="/A088557/b088557.txt">Table of n, a(n) for n = 1..1000</a>

%t a[n_] := 2k /. Solve[k > 0 && 1 < h < 2k + 2n + 1 && (2k)^2 + (2n + 1)^2 == h^2 && GCD[2k, 2n + 1, h] == 1, {k, h}, Integers][[1]];

%t a /@ Range[54] (* _Jean-François Alcover_, Mar 05 2020 *)

%Y Cf. A088558, A096891-A096900.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Nov 17 2003

%E Corrected and extended by _Ray Chandler_, Jul 14 2004