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%I #41 Sep 08 2022 08:45:25
%S 7,14,17,21,23,28,31,34,35,41,42,46,47,49,51,56,62,63,68,69,70,71,73,
%T 77,79,82,84,85,89,91,92,93,94,97,98,102,103,105,112,113,115,119,123,
%U 124,126,127,133,136,137,138,140,141,142,146,147,151,153,154,155,158,161,164,167,168,170,175,178,182,184,186,187,188
%N Sum of legs of Pythagorean triangles (without multiple entries).
%C The prime numbers in this sequence define A001132 (see comment in A001132). - _Richard Choulet_, Dec 16 2008
%C For the sum of legs of Pythagorean triangles with multiple entries see A198390. - _Wolfdieter Lang_, May 24 2013
%C Are these just the positive multiples of A001132? - _Charles R Greathouse IV_, May 28 2013
%C For the sum of legs of primitive Pythagorean triangles see A120681. - _Wolfdieter Lang_, Feb 17 2015
%C n is in the sequence iff A331671(n) > 0. - _Ray Chandler_, Feb 26 2020
%H Seiichi Manyama, <a href="/A118905/b118905.txt">Table of n, a(n) for n = 1..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PythagoreanTriple.html">Pythagorean Triple.</a>
%e 7 = 3 + 4 and 3^2 + 4^2 = 5^2.
%e a(14) = 49 = 7^2 from the primitive Pythagorean triangle (x,y,z) = (9,40,41), and from the non-primitive one 7*(3,4,5); a(42) = 119 = 7*17 from four Pythagorean triangles (39,80,89) and (99,20,181) (both primitive) and 7*(5,12,13), 17*(3,4,5). - _Wolfdieter Lang_, May 24 2013
%o (PARI) is(n)=my(t=n^2); forstep(i=2-n%2, n-2, 2, if(issquare((t+i^2)/2), return(1))); 0 \\ _Charles R Greathouse IV_, May 28 2013
%o (Magma) [m:m in [2..200]|#[k:k in [1..m-1]|IsSquare(k^2+(m-k)^2)] ne 0]; // _Marius A. Burtea_, Jul 29 2019
%Y Cf. A009096, A118903, A118904, A058529, A001132, A120681, A331671.
%K nonn
%O 1,1
%A _Giovanni Resta_, May 05 2006
%E More terms from 147 on. - _Richard Choulet_, Nov 24 2009
%E Name specified. - _Wolfdieter Lang_, May 24 2013
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