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A097700 Numbers not of form x^2 + 2y^2. 11

%I #9 Sep 08 2022 08:45:14

%S 5,7,10,13,14,15,20,21,23,26,28,29,30,31,35,37,39,40,42,45,46,47,52,

%T 53,55,56,58,60,61,62,63,65,69,70,71,74,77,78,79,80,84,85,87,90,91,92,

%U 93,94,95,101,103,104,105,106,109,110,111,112,115,116,117,119,120,122

%N Numbers not of form x^2 + 2y^2.

%C Is lim_{n->inf} a(n)/n = 3/4?

%H Vincenzo Librandi, <a href="/A097700/b097700.txt">Table of n, a(n) for n = 1..6800</a>

%t formQ[n_]:=Reduce[x>=0&&y>=0&&n==x^2 + 2 y^2, {x, y}, Integers]==False; Select[Range[0, 200], formQ] (* _Vincenzo Librandi_, Jan 15 2017 *)

%o (Magma) [n: n in [0..160] | NormEquation(2, n) eq false]; // _Vincenzo Librandi_, Jan 15 2017

%Y Complement of A002479.

%K nonn

%O 1,1

%A _Ralf Stephan_, Aug 23 2004

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