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Positive integers that are not the perimeter of any integer-sided right triangle.
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%I #6 Nov 10 2021 17:36:03

%S 1,2,3,4,5,6,7,8,9,10,11,13,14,15,16,17,18,19,20,21,22,23,25,26,27,28,

%T 29,31,32,33,34,35,37,38,39,41,42,43,44,45,46,47,49,50,51,52,53,54,55,

%U 57,58,59,61,62,63,64,65,66,67,68,69,71,73,74,75,76,77,78,79,81,82,83,85

%N Positive integers that are not the perimeter of any integer-sided right triangle.

%C Complement of A010814.

%t seq[max_] := Module[{s = {}, a, b, c}, Do[If[IntegerQ[c = Sqrt[a^2 + b^2]], AppendTo[s, a + b + c]], {a, max}, {b, Floor@Sqrt[a], a}]; Complement[Range[max], s]]; seq[100] (* _Amiram Eldar_, Oct 24 2021 *)

%Y Cf. A010814.

%K nonn

%O 1,2

%A _Wesley Ivan Hurt_, Oct 23 2021