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 A189737 #32 Feb 18 2024 03:34:15
%S A189737 3,3,18,63,243,918,3483,13203,50058,189783,719523,2727918,10342323,
%T A189737 39210723,148659138,563609583,2136806163,8101247238,30714160203,
%U A189737 116446222323,441481147578,1673782109703,6345789771843,24058715644638,91213516249443,345816695682243
%N A189737 a(1)=3, a(2)=3, a(n)=3*a(n-1) + 3*a(n-2).
%H A189737 Vincenzo Librandi, <a href="/A189737/b189737.txt">Table of n, a(n) for n = 1..100</a>
%H A189737 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,3).
%F A189737 G.f.: 3*x*(1-2*x)/(1-3*x-3*x^2). - _Bruno Berselli_, May 24 2011
%t A189737 LinearRecurrence[{3,3},{3,3},40]
%o A189737 (Maxima) a[1]:3$ a[2]:3$ a[n]:=3*a[n-1]+3*a[n-2]$ makelist(a[n], n, 1, 26); /* _Bruno Berselli_, May 24 2011 */
%Y A189737 Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189746, A189747, A189748, A189749.
%K A189737 nonn,easy
%O A189737 1,1
%A A189737 _Harvey P. Dale_, Apr 26 2011