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 A164118 #10 Oct 02 2023 11:35:48
%S A164118 1,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,
%T A164118 2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,
%U A164118 2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1,-2,-1,0,0,1,2,1,0,0,-1
%N A164118 Expansion of (1 - x^2) * (1 - x^4) * (1 - x^5) / ((1 - x) * (1 - x^10)) in powers of x.
%H A164118 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1, -1, 1, -1).
%F A164118 Euler transform of length 10 sequence [ 1, -1, 0, -1, -1, 0, 0, 0, 0, 1].
%F A164118 a(-n) = a(n). a(n + 5) = -a(n) unless n=0 or n=-5.
%F A164118 G.f.: (1 - x^4) / (1 - x + x^2 - x^3 + x^4).
%t A164118 CoefficientList[Series[(1 - x^4) / (1 - x + x^2 - x^3 + x^4), {x, 0, 50}], x] (* _G. C. Greubel_, Sep 12 2017 *)
%o A164118 (PARI) {a(n) = -(n==0) + [2, 1, 0, 0, -1, -2, -1, 0, 0, 1][n%10 + 1]}
%Y A164118 A164116(n) = (-1)^n * a(n). Convolution inverse of A164117.
%K A164118 sign,easy
%O A164118 0,6
%A A164118 _Michael Somos_, Aug 10 2009