This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A000024 M0368 N0139 #19 Oct 17 2017 03:58:56 %S A000024 1,1,2,2,7,10,20,36,65,118,221,409,776,1463,2788,5328,10222,19714, %T A000024 38054,73685,142944,277838,540889,1054535,2058537,4023278,7871313, %U A000024 15414638,30213190,59266422,116343776,228545682,449240740,883570480,1738769611,3423469891,6743730746 %N A000024 Number of positive integers <= 2^n of form x^2 + 10 y^2. %D A000024 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A000024 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A000024 D. Shanks and L. P. Schmid, <a href="http://dx.doi.org/10.1090/S0025-5718-1966-0210678-1">Variations on a theorem of Landau. Part I</a>, Math. Comp., 20 (1966), 551-569. %H A000024 <a href="/index/Qua#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)) %K A000024 nonn %O A000024 0,3 %A A000024 _N. J. A. Sloane_