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 A106259 #17 Jan 30 2020 21:29:15
%S A106259 1,6,60,648,7344,85536,1014336,12182400,147702528,1803907584,
%T A106259 22159733760,273508669440,3389106769920,42134712606720,
%U A106259 525323149885440,6565657319866368,82235651779657728,1031956779869798400
%N A106259 Expansion of 1/sqrt(1-12x-12x^2).
%C A106259 Central coefficient of (1+6x+12x^2)^n. Sixth binomial transform of 1/sqrt(1-48x^2). In general, 1/sqrt(1-4*r*x-4*r*x^2) has e.g.f. exp(2rx)BesselI(0,2r*sqrt((r+1)/r)x)), a(n)=sum{k=0..n, C(2k,k)C(k,n-k)r^k}, gives the central coefficient of (1+(2r)x+r(r+1)x^2) and is the (2r)-th binomial transform of 1/sqrt(1-8*C(n+1,2)x^2).
%H A106259 Vincenzo Librandi, <a href="/A106259/b106259.txt">Table of n, a(n) for n = 0..200</a>
%H A106259 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.
%F A106259 E.g.f.: exp(6*x)*BesselI(0, 6*sqrt(4/3)*x); a(n)=sum{k=0..n, C(2k, k)C(k, n-k)3^k}.
%F A106259 D-finite with recurrence: n*a(n) = 6*(2*n-1)*a(n-1) + 12*(n-1)*a(n-2). - _Vaclav Kotesovec_, Oct 17 2012
%F A106259 a(n) ~ (1+sqrt(3))*(6+4*sqrt(3))^n/(2*sqrt(2*Pi*n)). - _Vaclav Kotesovec_, Oct 17 2012
%t A106259 CoefficientList[Series[1/Sqrt[1-12*x-12*x^2], {x, 0, 20}], x] (* _Vaclav Kotesovec_, Oct 17 2012 *)
%Y A106259 Cf. A006139, A106258, A106260, A106261.
%K A106259 easy,nonn
%O A106259 0,2
%A A106259 _Paul Barry_, Apr 28 2005