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 A111665 #22 Mar 09 2024 16:26:32
%S A111665 1,2,3,4,5,10,23,56,141,366,955,2496,6529,17090,44739,117124,306629,
%T A111665 802762,2101655,5502200,14404941,37712622,98732923,258486144,
%U A111665 676725505,1771690370,4638345603,12143346436,31791693701,83231734666,217903510295
%N A111665 Expansion of (-1+x+2*x^2+5*x^4+3*x^3) / ((x-1)*(x+1)*(x^2-3*x+1)*(1+x^2)).
%C A111665 Floretion Algebra Multiplication Program, FAMP Code: 4ibaseisumseq[ + .25'i + .25i' + .25'ii' + .25'jj' + .25'kk' + .25'jk' + .25'kj' + .25e], sumtype: Y[15],inty[ * ]
%H A111665 Colin Barker, <a href="/A111665/b111665.txt">Table of n, a(n) for n = 0..1000</a>
%H A111665 Robert Munafo, <a href="https://mrob.com/pub/seq/floretion.html">Sequences Related to "Floretions"</a>
%H A111665 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (3,-1,0,1,-3,1).
%F A111665 a(n) = 3*a(n-1) - a(n-2) + a(n-4) - 3*a(n-5) + a(n-6) for n>5. - _Colin Barker_, May 13 2019
%t A111665 LinearRecurrence[{3, -1, 0, 1, -3, 1}, {1, 2, 3, 4, 5, 10}, 50] (* _Paolo Xausa_, Mar 09 2024 *)
%o A111665 (PARI) Vec((1 - x - 2*x^2 - 3*x^3 - 5*x^4) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)*(1 + x^2)) + O(x^35)) \\ _Colin Barker_, May 13 2019
%Y A111665 Cf. A111664, A111666.
%K A111665 easy,nonn
%O A111665 0,2
%A A111665 _Creighton Dement_, Aug 14 2005