%I A000024 M0368 N0139
%S A000024 1,1,2,2,7,10,20,36,65,118,221,409,776,1463,2788,5328,10222,19714,38054,
%T A000024 73685,142944,277838,540889,1054535,2058537,4023278,7871313,15414638,30213190,
%U A000024 59266422,116343776,228545682,449240740,883570480,1738769611,3423469891,
               6743730746
%N A000024 Number of positive integers <= 2^n of form x^2 + 10 y^2.
%D A000024 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A000024 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A000024 D. Shanks and L. P. Schmid, Variations on a theorem of Landau. Part I, 
               Math. Comp., 20 (1966), 551-569.
%H A000024 <a href="Sindx_Qua.html#quadpop">Index entries for sequences related 
               to populations of quadratic forms</a>
%o A000024 (PARI) a(n)=local(A);if(n<0,0,A=qfrep([1,0;0,10],2^n);sum(k=1,2^n,A[k]!=0))
%Y A000024 Sequence in context: A101372 A133374 A054226 this_sequence A005223 A118680 
               A094116
%Y A000024 Adjacent sequences: A000021 A000022 A000023 this_sequence A000025 A000026 
               A000027
%K A000024 nonn
%O A000024 0,3
%A A000024 N. J. A. Sloane (njas(AT)research.att.com).