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 A120468 #18 Jun 02 2025 00:29:38
%S A120468 0,16,24,142,240,1276,2184,11482,19680,103336,177144,930022,1594320,
%T A120468 8370196,14348904,75331762,129140160,677985856,1162261464,6101872702,
%U A120468 10460353200,54916854316,94143178824,494251688842,847288609440
%N A120468 Expansion of -2*x*(-8-12*x+9*x^2) / ( (x-1)*(3*x-1)*(3*x+1)*(1+x) ).
%H A120468 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,10,0,-9).
%F A120468 8*a(n) = (-1)^(n+1) * (13+3^(n+2)) + 11*(3^(n+1) -1). - _R. J. Mathar_, Nov 07 2011
%F A120468 a(2n+1) = 2*A187709(n+1). - _R. J. Mathar_, Nov 07 2011
%t A120468 LinearRecurrence[{0,10,0,-9},{0,16,24,142},30] (* _Harvey P. Dale_, Dec 06 2023 *)
%K A120468 nonn,easy,less
%O A120468 0,2
%A A120468 _Roger L. Bagula_ and _Gary W. Adamson_, Jul 04 2006