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 A111913 #19 Mar 11 2024 03:49:03
%S A111913 0,2,3,3,3,3,6,4,5,1,5,1,4,-2,1,-3,1,-3,-2,-4,-1,-1,-1,-1,0,2,3,3,3,3,
%T A111913 6,4,5,1,5,1,4,-2,1,-3,1,-3,-2,-4,-1,-1,-1,-1,0,2,3,3,3,3,6,4,5,1,5,1,
%U A111913 4,-2,1,-3,1,-3,-2,-4,-1,-1,-1,-1,0,2,3,3,3,3,6,4,5,1,5,1,4,-2,1,-3,1,-3,-2,-4,-1,-1,-1,-1,0,2,3,3
%N A111913 Expansion of x*(-2-3*x-x^2+x^7+x^8+2*x^4) / ((x-1)*(x+1)*(x^8-x^4+1)).
%C A111913 It appears that (a(n)) has period 24.
%C A111913 The above conjecture is correct, since x^24 = 1 mod (x-1)*(x+1)*(x^8-x^4+1). - _Charles R Greathouse IV_, Feb 07 2013
%C A111913 Floretion Algebra Multiplication Program, FAMP Code: 4ibasesigcycsumseq[ + .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.
%H A111913 Colin Barker, <a href="/A111913/b111913.txt">Table of n, a(n) for n = 0..1000</a>
%H A111913 <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,0,1,0,-1,0,-1,0,1).
%F A111913 a(n) = a(n-2) + a(n-4) - a(n-6) - a(n-8) + a(n-10) for n>9. - _Colin Barker_, May 18 2019
%t A111913 LinearRecurrence[{0,1,0,1,0,-1,0,-1,0,1},{0,2,3,3,3,3,6,4,5,1},120] (* _Harvey P. Dale_, Apr 14 2019 *)
%o A111913 (PARI) a(n)=[0,2,3,3,3,3,6,4,5,1,5,1,4,-2,1,-3,1,-3,-2,-4,-1,-1,-1,-1][n%24+1] \\ _Charles R Greathouse IV_, Feb 07 2013
%o A111913 (PARI) concat(0, Vec(x*(2 + 3*x + x^2 - 2*x^4 - x^7 - x^8) / ((1 - x)*(1 + x)*(1 - x^4 + x^8)) + O(x^80))) \\ _Colin Barker_, May 18 2019
%Y A111913 Cf. A111912, A111914, A111915, A085846.
%K A111913 easy,sign
%O A111913 0,2
%A A111913 _Creighton Dement_, Aug 20 2005