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Primitive Pythagorean Quadruples a^2+b^2+c^2=d^2, 0<a<=b<=c<=d, gcd(a,b,c,d)=1, sorted by d, then c, then b; sequence gives short even leg values.
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%I #3 Mar 30 2012 17:29:19

%S 2,2,4,4,6,2,4,2,2,8,12,6,6,6,8,4,4,4,6,14,6,12,12,14,10,2,2,2,12,12,

%T 16,14,6,6,6,20,8,16,4,8,4,8,18,6,18,6,8,12,24,8,22,14,2,14,2,10,24,

%U 12,24,4,4,18,30,18,2,6,2,20,4,16,16,8,8,18,18,6,18,2,6,24,12,32,4,24,12

%N Primitive Pythagorean Quadruples a^2+b^2+c^2=d^2, 0<a<=b<=c<=d, gcd(a,b,c,d)=1, sorted by d, then c, then b; sequence gives short even leg values.

%C One of a,b,c is odd, other two are even for primitive Pythagorean quadruples.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PythagoreanQuadruple.html">Pythagorean Quadruple.</a>

%Y Cf. A096907, A096908, A096909.

%K nonn

%O 1,1

%A _Ray Chandler_, Aug 15 2004