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 A274110 #26 Mar 15 2023 15:20:26
%S A274110 1,2,3,5,8,14,24,42,73,128,224,393,689,1209,2121,3722,6531,11461,
%T A274110 20112,35294,61936,108690,190737,334720,587392,1030801,1808929,
%U A274110 3174449,5570769,9776018,17155715,30106181,52832664,92714862,162703240,285524282,501060185,879299328,1543062752,2707886361
%N A274110 Number of equivalence classes of ballot paths of length n for the string uu.
%H A274110 Vincenzo Librandi, <a href="/A274110/b274110.txt">Table of n, a(n) for n = 1..1000</a>
%H A274110 K. Manes, A. Sapounakis, I. Tasoulas, and P. Tsikouras, <a href="http://arxiv.org/abs/1510.01952">Equivalence classes of ballot paths modulo strings of length 2 and 3</a>, arXiv:1510.01952 [math.CO], 2015.
%H A274110 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-1,1,-1).
%F A274110 G.f.: x*(1-x^2-x^4) / ( (x-1)*(1+x)*(x^3-x^2+2*x-1) ). - _R. J. Mathar_, Jun 20 2016
%F A274110 a(n) = 2*a(n-1) - a(n-3) + a(n-4) - a(n-5). - _Wesley Ivan Hurt_, Mar 15 2023
%t A274110 CoefficientList[Series[(1 - x^2 - x^4) / ((x - 1) (1 + x) (x^3 - x^2 + 2 x - 1)), {x, 0, 40}], x] (* _Vincenzo Librandi_, Aug 18 2016 *)
%o A274110 (PARI) apply( {A274110(n)=(matcompanion(x^5-2*x^4+x^2-x+1)^n)[5,3]+1}, [1..44]) \\ _M. F. Hasler_, Jun 22 2021
%K A274110 nonn,easy
%O A274110 1,2
%A A274110 _N. J. A. Sloane_, Jun 17 2016