|
%I #6 Jun 08 2014 17:19:52
%S 0,1,4,9,11,12,15,16,20,25,27,36,44,45,47,48,49,53,60,64,69,75,80,81,
%T 92,93,99,100,103,108,111,115,121,124,125,132,135,144,148,155,163,165,
%U 169,176,177,180,185,188,192,196,199,201,207,212,213,220,225,236,240,243,256,257,267,268,269,275
%N Nonnegative integers of the form x^2+11y^2.
%C Discriminant -44.
%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(1,0,11,500);
%Y Primes: A033209.
%K nonn
%O 0,3
%A _N. J. A. Sloane_, Jun 08 2014
|
