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 A102653 #33 Mar 12 2024 14:05:29
%S A102653 4,12,28,56,112,228,460,920,1840,3684,7372,14744,29488,58980,117964,
%T A102653 235928,471856,943716,1887436,3774872,7549744,15099492,30198988,
%U A102653 60397976,120795952,241591908,483183820,966367640,1932735280,3865470564,7730941132,15461882264
%N A102653 a(n) = 4 * floor(9*2^n/5).
%C A102653 In binary, each term differs from the previous by a single bit.
%H A102653 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,3,-2).
%F A102653 From _R. J. Mathar_, Feb 20 2011: (Start)
%F A102653 a(n) = 4 * A151754(n+1).
%F A102653 G.f.: 4 * ( 1+x^2-x^3 ) / ( (x-1)*(2*x-1)*(x^2+1) ). (End)
%F A102653 a(0)=4, a(1)=12, a(2)=28, a(3)=56, a(n) = 3*a(n-1)-3*a(n-2)+3*a(n-3)-2*a(n-4). - _Harvey P. Dale_, Jun 15 2011
%t A102653 Table[4Floor[(27 2^n)/15],{n,0,30}] (* or *) LinearRecurrence[ {3,-3,3,-2}, {4,12,28,56},30] (* _Harvey P. Dale_, Jun 15 2011 *)
%o A102653 (PARI) a(n)=27<<n\15*4 \\ _Charles R Greathouse IV_, Feb 04 2016
%Y A102653 Cf. A102650, A102651, A102652.
%K A102653 easy,nonn,less
%O A102653 0,1
%A A102653 _Odimar Fabeny_, Feb 02 2005
%E A102653 Edited by _Don Reble_, Mar 28 2006