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 A291779 #13 Apr 02 2019 11:49:17
%S A291779 0,1,2,4,12,24,48,112,224,448,960,1920,3840,7936,15872,31744,64512,
%T A291779 129024,258048,520192,1040384,2080768,4177920,8355840,16711680,
%U A291779 33488896,66977792,133955584,268173312,536346624,1072693248,2146435072,4292870144,8585740288,17175674880,34351349760,68702699520
%N A291779 a(n) = 2^n - 2^floor(2n/3).
%H A291779 Robert Israel, <a href="/A291779/b291779.txt">Table of n, a(n) for n = 0..3318</a>
%H A291779 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,4,-8).
%F A291779 G.f.: x/((1-2*x)*(1-4*x^3)). - _Robert Israel_, Sep 01 2017
%p A291779 seq(2^n-2^floor(2*n/3),n=0..50); # _Robert Israel_, Sep 01 2017
%t A291779 LinearRecurrence[{2, 0, 4, -8}, {0, 1, 2, 4}, 37] (* _Jean-François Alcover_, Apr 02 2019 *)
%Y A291779 Cf. A004523, A291778.
%K A291779 nonn
%O A291779 0,3
%A A291779 _Don Reble_ and _N. J. A. Sloane_, Sep 01 2017