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 A000801 M1015 N0381 #29 Feb 01 2022 02:34:57
%S A000801 2,4,6,10,16,26,44,76,132,234,420,761,1391,2561,4745,8841,16551,31114,
%T A000801 58708,111136,211000,401650,766372,1465422,2807599,5388709,10359735,
%U A000801 19946715,38459505,74250899,143524565,277742293,538043341,1043333611,2025040421
%N A000801 a(n) = Sum_{k = 1..n} floor(2^k / k).
%D A000801 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A000801 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A000801 T. D. Noe, <a href="/A000801/b000801.txt">Table of n, a(n) for n = 1..500</a>
%p A000801 A000801 := proc(n) local k; sum(floor(2^k/k),k=1..n); end;
%t A000801 Table[Sum[Floor[2^k/k], {k, n}], {n, 30}] (* _T. D. Noe_, Jun 20 2012 *)
%Y A000801 Cf. A000799.
%K A000801 nonn
%O A000801 1,1
%A A000801 _N. J. A. Sloane_