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 A111914 #11 May 18 2019 07:14:00 %S A111914 0,0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0, %T A111914 0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0,0, %U A111914 1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4,-3,-1,1,1,0,0,1,1,-1,-3,-4,-4,-5,-7,-9,-9,-8,-8,-9,-9,-7,-5,-4,-4 %N A111914 Expansion of -x^2*(x^4-2*x^3+x^2-2*x+1)*(x+1)^2 / ((x-1)*(x^8-x^4+1)). %C A111914 It appears that (a(n)) has period 24. %H A111914 Colin Barker, <a href="/A111914/b111914.txt">Table of n, a(n) for n = 0..1000</a> %H A111914 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1,0,0,-1,1). %F A111914 a(n) = a(n-1) + a(n-4) - a(n-5) - a(n-8) + a(n-9) for n > 8. - _Colin Barker_, May 18 2019 %o A111914 4jbasesigcycsumseq[ + .5'i + .5j' + .5'ij' + .5e], sumtype: Y[8] = (int)Y[6] - (int)Y[7] + Y[8] + sum (internal program code); apart from initial term 0. %o A111914 (PARI) concat([0,0], Vec(x^2*(1 + x)^2*(1 - 2*x + x^2 - 2*x^3 + x^4) / ((1 - x)*(1 - x^4 + x^8)) + O(x^40))) \\ _Colin Barker_, May 18 2019 %Y A111914 Cf. A111912, A111913, A111915, A085846. %K A111914 easy,sign %O A111914 0,6 %A A111914 _Creighton Dement_, Aug 20 2005