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 A098272 #22 Sep 08 2022 08:45:14
%S A098272 2,8,96,1536,28160,559104,11698176,254017536,5670567936,129328742400,
%T A098272 3000426823680,70587116421120,1679973370822656,40376795886780416,
%U A098272 978590323955466240,23890230876435382272,586939535850605641728
%N A098272 a(n) = 2^(2n+1) * binomial(3n,n)/(2n+1).
%H A098272 Vincenzo Librandi, <a href="/A098272/b098272.txt">Table of n, a(n) for n = 0..100</a>
%H A098272 M. Bousquet-Mélou, <a href="http://arXiv.org/abs/math.CO/0401067">Walks in the quarter plane: Kreweras' algebraic model</a>, arXiv:math/0401067 [math.CO], 2004-2006.
%F A098272 G.f. satisfies A(x) = Sum_{n>=0} a(n)*x^(3n+1) = x(2 + A(x)^3).
%F A098272 a(n) = 2n * A006335(n) = 2^(2n+1) * A001764(n).
%F A098272 G.f.: (2 sin(1/3*arcsin(3*sqrt(3)*sqrt(x))))/(sqrt(3)*sqrt(x)). - _Harvey P. Dale_, Oct 02 2011
%F A098272 E.g.f.: 2*2F2(1/3,2/3; 1,3/2; 27*x). - _Ilya Gutkovskiy_, Jan 25 2017
%t A098272 Table[2^(2n+1) Binomial[3n,n]/(2n+1),{n,0,20}] (* _Harvey P. Dale_, Oct 02 2011 *)
%o A098272 (PARI) a(n)=2^(2*n+1)*binomial(3*n,n)/(2*n+1)
%o A098272 (PARI) a(n)=polcoeff(serreverse(Ser(x/(2+x^3))),3*n+1)
%o A098272 (Magma) [2^(2*n+1)*Binomial(3*n, n)/(2*n+1): n in [0..20]]; // _Vincenzo Librandi_, Oct 03 2011
%Y A098272 Cf. A001764, A006335.
%K A098272 nonn
%O A098272 0,1
%A A098272 _Ralf Stephan_, Sep 02 2004