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 A307466 #4 Apr 09 2019 12:05:09 %S A307466 1,1,2,5,14,41,121,355,1032,2974,8509,24210,68595,193753,546041, %T A307466 1536358,4317652,12123685,34021810,95431301,267601625,750221859, %U A307466 2102913404,5893910702,16517729313,46288368894,129710571239,363467837569,1018468044881,2853791650010 %N A307466 Number of Catalan words of length n avoiding the pattern 210. %H A307466 J.-L. Baril, S. Kirgizov, V. Vanjovszki, <a href="http://doi.org/10.1016/j.disc.2018.06.001">Descent distribution on Catalan words avoiding a pattern of length at most three</a>, Disc. Math. 341 (2018) 2608-2615, Table 2. %H A307466 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (6,-11,5,2). %F A307466 a(n) = A215404(n+2) -2*A215404(n+1) - A215404(n) -2^(n-1), n>0. %F A307466 G.f.: (1-5*x+7*x^2-x^3-x^4)/(1-2*x)/(1-4*x+3*x^2+x^3) . %p A307466 (1-5*x+7*x^2-x^3-x^4)/(1-2*x)/(1-4*x+3*x^2+x^3) ; %p A307466 taylor(%,x=0,30) ; %p A307466 gfun[seriestolist](%) ; %K A307466 nonn,easy %O A307466 0,3 %A A307466 _R. J. Mathar_, Apr 09 2019