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 A107849 #21 Feb 20 2024 01:09:26
%S A107849 1,2,2,4,5,6,12,16,25,42,58,92,141,206,324,488,737,1138,1714,2612,
%T A107849 3989,6038,9212,14016,21289,32442,49322,75020,114205,173662,264244,
%U A107849 402072,611569,930562,1415714,2153700,3276837,4985126,7584236,11538800
%N A107849 Expansion of (1 + x)^2 / ((1 - x^2 - 2*x^3)*(1 + x^4)).
%H A107849 Colin Barker, <a href="/A107849/b107849.txt">Table of n, a(n) for n = 0..1000</a>
%H A107849 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,2,-1,0,1,2).
%F A107849 a(n) = A052947(n+2) + A014017(n+6). - _Ralf Stephan_, Nov 30 2010
%F A107849 a(n) = a(n-2) + 2*a(n-3) - a(n-4) + a(n-6) + 2*a(n-7) for n>6. - _Colin Barker_, Apr 30 2019
%t A107849 CoefficientList[Series[(1 + x)^2 / ((1 - x^2 - 2*x^3)*(1 + x^4)),{x,0,39}],x] (* _James C. McMahon_, Feb 19 2024 *)
%o A107849 (PARI) Vec((1 + x)^2 / ((1 - x^2 - 2*x^3)*(1 + x^4)) + O(x^45)) \\ _Colin Barker_, Apr 30 2019
%Y A107849 Cf. A107850, A107851, A107852.
%K A107849 easy,nonn
%O A107849 0,2
%A A107849 _Creighton Dement_, May 25 2005