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 A189743 #33 May 17 2025 22:42:42
%S A189743 4,4,32,144,704,3392,16384,79104,381952,1844224,8904704,42995712,
%T A189743 207601664,1002389504,4839964672,23369416704,112837525504,
%U A189743 544827768832,2630661177344,12701955784704,61330467848192,296129694531584,1429840649519104,6903881376202752
%N A189743 a(1)=4, a(2)=4, a(n) = 4*a(n-1) + 4*a(n-2).
%H A189743 Vincenzo Librandi, <a href="/A189743/b189743.txt">Table of n, a(n) for n = 1..100</a>
%H A189743 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4,4).
%F A189743 G.f.: 4*x*(1-3*x)/(1-4*x-4*x^2). - _Bruno Berselli_, May 24 2011
%t A189743 LinearRecurrence[{4,4},{4,4},40]
%o A189743 (Maxima) a[1]:4$ a[2]:4$ a[n]:=4*a[n-1]+4*a[n-2]$ makelist(a[n], n, 1, 24); /* _Bruno Berselli_, May 24 2011 */
%Y A189743 Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189737, A189738, A189739, A189741, A189742, A189744, A189745, A189746, A189747, A189748, A189749.
%K A189743 nonn,easy
%O A189743 1,1
%A A189743 _Harvey P. Dale_, Apr 26 2011