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 A322040 #13 Jan 20 2021 12:33:09
%S A322040 1,0,0,4,-4,4,8,-20,32,-12,-40,124,-160,68,232,-628,816,-300,-1160,
%T A322040 3100,-3904,1380,5640,-14676,18256,-6156,-26472,67900,-83488,27268,
%U A322040 121640,-308276,375920,-119532,-549448,1379932,-1671424,520100,2449480
%N A322040 Expansion of (1 + x)^2 / ((1 - x)^2*(1 + 2*x + 2*x^2)^2).
%C A322040 Connected with tiling of torus by squares (see A322038).
%H A322040 Colin Barker, <a href="/A322040/b322040.txt">Table of n, a(n) for n = 0..1000</a>
%H A322040 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (-2,-1,4,4,0,-4).
%F A322040 a(n) = -2*a(n-1) - a(n-2) + 4*a(n-3) + 4*a(n-4) - 4*a(n-6) for n>5. - _Colin Barker_, Dec 04 2018
%t A322040 LinearRecurrence[{-2, -1, 4, 4, 0, -4}, {1, 0, 0, 4, -4, 4}, 100] (* _Amiram Eldar_, Dec 04 2018 *)
%t A322040 CoefficientList[Series[(1+x)^2/((1-x)^2(1+2x+2x^2)^2),{x,0,40}],x] (* _Harvey P. Dale_, Jan 20 2021 *)
%o A322040 (PARI) Vec((1 + x)^2 / ((1 - x)^2*(1 + 2*x + 2*x^2)^2) + O(x^40)) \\ _Colin Barker_, Dec 04 2018
%Y A322040 Cf. A322038, A322039.
%K A322040 sign,easy
%O A322040 0,4
%A A322040 _N. J. A. Sloane_, Dec 03 2018