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 A099606 #5 Mar 07 2024 14:04:32
%S A099606 1,4,10,48,116,560,1352,6528,15760,76096,183712,887040,2141504,
%T A099606 10340096,24963200,120532992,290992384,1405035520,3392055808,
%U A099606 16378294272,39540700160,190919389184,460920178688,2225519493120,5372879343616
%N A099606 Row sums of triangle A099605, in which row n equals the inverse Binomial transform of column n of the triangle A034870 of even-indexed rows of Pascal's triangle.
%H A099606 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 12, 0, -4).
%F A099606 a(n) = Pell(n+1)*2^[(n+1)/2]. a(n) = 12*a(n-2) - 4*a(n-4) for n>=4. G.f.: (1+4*x-2*x^2)/(1-12*x^2+4*x^4).
%e A099606 Sequence begins: {1*1, 2*2, 5*2, 12*4, 29*4, 70*8, 169*8, 408*16, ...}.
%o A099606 (PARI) a(n)=polcoeff((1+4*x-2*x^2)/(1-12*x^2+4*x^4)+x*O(x^n),n)
%Y A099606 Cf. A099603, A099605, A034870, A000129.
%K A099606 nonn
%O A099606 0,2
%A A099606 _Paul D. Hanna_, Oct 25 2004