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%I #6 Jun 08 2014 16:07:53
%S 0,1,4,9,12,14,16,18,24,25,32,36,42,47,48,49,51,54,56,63,64,68,72,81,
%T 83,84,96,100,102,106,108,111,112,118,121,122,126,128,136,144,147,148,
%U 162,168,169,178,188,189,191,192,194,196,197,204,213,216,222,224,225,237,238,243,252,256,262,269
%N Nonnegative integers of the form x^2+xy+12y^2.
%C Discriminant -47.
%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)
%p fd:=proc(a,b,c,M) local dd,xlim,ylim,x,y,t1,t2,t3,t4,i;
%p dd:=4*a*c-b^2;
%p if dd<=0 then error "Form should be positive definite."; break; fi;
%p t1:={};
%p xlim:=ceil( sqrt(M/a)*(1+abs(b)/sqrt(dd)));
%p ylim:=ceil( 2*sqrt(a*M/dd));
%p for x from 0 to xlim do
%p for y from -ylim to ylim do
%p t2 := a*x^2+b*x*y+c*y^2;
%p if t2 <= M then t1:={op(t1),t2}; fi; od: od:
%p t3:=sort(convert(t1,list));
%p t4:=[];
%p for i from 1 to nops(t3) do
%p if isprime(t3[i]) then t4:=[op(t4),t3[i]]; fi; od:
%p [[seq(t3[i],i=1..nops(t3))], [seq(t4[i],i=1..nops(t4))]];
%p end;
%p fd(1,1,12,500);
%Y Primes: A033232.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Jun 08 2014
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