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 A000690 M0586 N0212 #32 May 13 2022 18:49:36 %S A000690 1,2,3,4,7,13,24,44,83,157,297,567,1085,2086,4019,7766,15039,29181, %T A000690 56717,110408,215225,420076,820836,1605587,3143562,6160098,12080946, %U A000690 23710229,46565965,91512121,179947985,354043613,696935548,1372589372 %N A000690 Landau's approximation to population of x^2 + y^2 <= 2^n. %D A000690 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A000690 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A000690 Sean A. Irvine, <a href="/A000690/b000690.txt">Table of n, a(n) for n = 0..999</a> %H A000690 D. Shanks, <a href="http://dx.doi.org/10.1090/S0025-5718-1964-0159174-9">The second-order term in the asymptotic expansion of B(x)</a>, Mathematics of Computation 18 (1964), pp. 75-86. %H A000690 <a href="/index/Qua#quadpop">Index entries for sequences related to populations of quadratic forms</a> %F A000690 a(n) = round(b*2^n/sqrt(log(2^n))) where b=0.764223654... is the Landau-Ramanujan constant (A064533). %Y A000690 Cf. A000050, A064533. %K A000690 nonn %O A000690 0,2 %A A000690 _N. J. A. Sloane_ %E A000690 More terms from _Sean A. Irvine_, Feb 23 2011 %E A000690 Name clarified by _Seth A. Troisi_, Apr 28 2022