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Number of solutions to n = 2*u^2 + 3*v^2, u*v>0.
3

%I #5 Feb 09 2017 12:36:44

%S 0,0,0,0,1,0,0,0,0,0,1,0,0,1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,1,0,0,0,0,

%T 2,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,1,0,0,0,1,0,0,

%U 0,0,0,0,0,0,1,0,2,0,0,1,0,0,1,1,0,0,0,0,0,0,0,0,1,0,0,0,0,1,1,0,1,0

%N Number of solutions to n = 2*u^2 + 3*v^2, u*v>0.

%C a(A084864(n)) > 0.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DiophantineEquation2ndPowers.html">Diophantine Equation: 2nd Powers.</a>

%e n=770 = 2*19^2 + 3*4^2 = 2*17^2 + 3*8^2 = 2*13^2 + 3*12^2 = 2*1 +

%e 3*16^2, therefore a(770)=4.

%Y Cf. A084865, A084866.

%K nonn

%O 1,35

%A _Reinhard Zumkeller_, Jun 10 2003