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 A098336 #41 Jan 30 2020 21:29:15
%S A098336 1,2,0,-16,-56,-48,384,1920,3168,-8512,-66560,-161280,113920,2224640,
%T A098336 7311360,3354624,-69253632,-306754560,-408059904,1898029056,
%U A098336 12054196224,25377005568,-38874316800,-443400781824,-1289598418944
%N A098336 Expansion of 1/sqrt(1 - 4*x + 12*x^2).
%C A098336 Central coefficients of (1 + 2*x - 2*x^2)^n.
%C A098336 Binomial transform of A098332.
%C A098336 Diagonal of rational function 1/(1 - (2*x^2 + 2*x*y - y^2)). - _Gheorghe Coserea_, Aug 04 2018
%H A098336 G. C. Greubel, <a href="/A098336/b098336.txt">Table of n, a(n) for n = 0..1000</a>
%H A098336 Hacène Belbachir, Abdelghani Mehdaoui, László Szalay, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL22/Szalay/szalay42.html">Diagonal Sums in the Pascal Pyramid, II: Applications</a>, J. Int. Seq., Vol. 22 (2019), Article 19.3.5.
%H A098336 Tony D. Noe, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL9/Noe/noe35.html">On the Divisibility of Generalized Central Trinomial Coefficients</a>, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.7.
%F A098336 E.g.f.: exp(2*x)*BesselI(0, 2*sqrt(-2)*x).
%F A098336 a(n) = Sum_{k=0..floor(n/2)} binomial(n, k)*binomial(n-k, k)* 2^n* (-2)^(-k).
%F A098336 a(n) = Sum_{k=0..floor(n/2)} binomial(n, k)*binomial(2(n-k), k)*(-3)^k. - _Paul Barry_, Sep 08 2004
%F A098336 D-finite with recurrence: n*a(n) + 2*(-2*n+1)*a(n-1) + 12*(n-1)*a(n-2) = 0. - _R. J. Mathar_, Nov 24 2012
%F A098336 G.f.: G(0), where G(k) = 1 + 2*x*(1-3*x)*(4*k+1)/( 2*k+1 - x*(1-3*x)*(2*k+1)*(4*k+3)/(x*(1-3*x)*(4*k+3) + (k+1)/G(k+1) )); (continued fraction). - _Sergei N. Gladkovskii_, Jun 30 2013
%F A098336 Lim sup_{n->infinity} |a(n)|/((2*sqrt(3))^n/sqrt(Pi*n)) = 6^(1/4). - _Vaclav Kotesovec_, Oct 09 2013
%F A098336 a(n) = 2^n*hypergeom([-n/2, 1/2-n/2], [1], -2). - _Peter Luschny_, Sep 18 2014
%p A098336 A098336 := n -> 2^n*hypergeom([-n/2, 1/2-n/2], [1], -2);
%p A098336 seq(round(evalf(A098336(n),99)),n=0..30); # _Peter Luschny_, Sep 18 2014
%t A098336 CoefficientList[Series[1/Sqrt[1-4*x+12*x^2], {x, 0, 20}], x] (* _Vaclav Kotesovec_, Oct 09 2013 *)
%o A098336 (PARI) Vec(1/sqrt(1-4*x+12*x^2) + O(x^50)) \\ _G. C. Greubel_, Jan 30 2017
%K A098336 sign,easy
%O A098336 0,2
%A A098336 _Paul Barry_, Sep 03 2004