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Positive integers a for which there is a primitive (-4)-Pythagorean triple (a,b,c) satisfying a<=b.
6

%I #5 Mar 30 2012 18:57:49

%S 1,3,4,4,5,5,7,7,8,8,9,11,11,12,12,13,13,15,15,16,16,17,17,19,19,20,

%T 20,20,20,21,21,23,23,24,24,25,28,28,28,28,29,31,32,32,33,35,35,35,36,

%U 37,39,40,40,40,44,44,44,45,48,51,52,52,52,55,55,56,56

%N Positive integers a for which there is a primitive (-4)-Pythagorean triple (a,b,c) satisfying a<=b.

%C See A195770 for definitions of k-Pythagorean triple, primitive k-Pythagorean triple, and lists of related sequences.

%e Primitive (-4)-Pythagorean triples a,b,c;

%e c^2=a^2+b^2+k*a*b, where k=-4:

%e 1,4,1

%e 3,20,13

%e 4,15,1

%e 4,21,11

%e 5,24,11

%e 5,48,37

%e 7,40,23

%e 7,88,73

%e 8,35,13

%e 8,65,47

%t (See A196376.)

%Y Cf. A195770, A196376, A196380, A196381.

%K nonn

%O 1,2

%A _Clark Kimberling_, Oct 01 2011