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 A107388 #17 Jun 17 2023 16:42:12
%S A107388 0,1,-1,2,4,21,75,286,1064,3977,14839,55386,206700,771421,2878979,
%T A107388 10744502,40099024,149651601,558507375,2084377906,7779004244,
%U A107388 29031639077,108347552059,404358569166,1509086724600,5631988329241,21018866592359,78443478040202
%N A107388 Expansion of x*(3*x-1)*(2*x-1) / ( (1-x)*(1+x)*(x^2-4*x+1) ).
%C A107388 One of the components of the n-th power of the 4X4 matrix with rows (0,1,0,0), (0,0,1,0), (0,0,0,1), (1,4,0,-4) multiplied by the vector (0,1,1,2).
%H A107388 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (4,0,-4,1).
%F A107388 a(n) = (-1)^(n+1)+(3*A001353(n+1)-11*A001353(n)-1)/2. - _R. J. Mathar_, Jul 10 2012
%F A107388 a(n) -a(n-2) = A001834(n-3). - _R. J. Mathar_, Dec 17 2017
%t A107388 CoefficientList[Series[x(3x-1)(2x-1)/((1-x)(1+x)(x^2-4x+1)),{x,0,40}],x] (* or *) LinearRecurrence[ {4,0,-4,1},{0,1,-1,2},40] (* _Harvey P. Dale_, Jun 17 2023 *)
%K A107388 sign,easy
%O A107388 0,4
%A A107388 _Roger L. Bagula_, May 24 2005, corrected Sep 04 2008
%E A107388 Sign of a(2) flipped. - _R. J. Mathar_, Jul 10 2012