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 A091596 #14 Jan 01 2024 11:06:16
%S A091596 0,1,2,5,12,27,62,137,304,663,1442,3109,6676,14259,30342,64321,135928,
%T A091596 286415,601962,1262173,2640860,5514731,11495502,23923065,49710272,
%U A091596 103148807,213754162,442421397,914668964,1888990243,3897285142
%N A091596 Expansion of x(1-2x^2)/(1-x-2x^2)^2.
%C A091596 Second column of A091595.
%H A091596 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,3,-4,-4).
%t A091596 CoefficientList[Series[x (1-2x^2)/(1-x-2x^2)^2,{x,0,30}],x] (* or *) LinearRecurrence[{2,3,-4,-4},{0,1,2,5},40] (* _Harvey P. Dale_, Dec 01 2015 *)
%K A091596 easy,nonn
%O A091596 0,3
%A A091596 _Paul Barry_, Jan 23 2004