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 A005818 Numbers n that are primitive solutions to n^2 = a^2 + b^2 + c^2 (a,b,c > 0). 3

%I

%S 3,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,

%T 53,55,57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93,95,97,

%U 99,101,103,105,107,109,111,113,115,117,119,121,123,125,127,129,131

%N Numbers n that are primitive solutions to n^2 = a^2 + b^2 + c^2 (a,b,c > 0).

%C These are the odd numbers excluding 1 and 5. Every term in A005767 is n*2^k for some k.

%H T. D. Noe, <a href="/A005818/b005818.txt">Table of n, a(n) for n = 1..1000</a>

%F G.f.: x*(-2*x^2 + x + 3)/(x - 1)^2. - _Chai Wah Wu_, Sep 14 2018

%Y Cf. A005767.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, RALPH PETERSON (ralphp(AT)LIBRARY.NRL.NAVY.MIL)

%E Name corrected by _T. D. Noe_, Nov 12 2010

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Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)