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 A099528 #5 Mar 30 2012 18:36:43
%S A099528 1,5,17,63,242,922,3502,13311,50608,192398,731429,2780649,10571120,
%T A099528 40187929,152781292,580824261,2208102985,8394481949,31913061839,
%U A099528 121322974122,461230079570,1753445197282,6666022438759,25342026784200
%N A099528 Row sums of triangle A099527, so that a(n) = Sum_{k=0..n} coefficient of z^k in (2 + 3*z + z^2)^(n-[k/2]), where [k/2] is the integer floor of k/2.
%F A099528 G.f.: (1+x-x^2)/(1-4*x+2*x^2-5*x^3+x^4).
%o A099528 (PARI) a(n)=sum(k=0,n,polcoeff((2+3*z+z^2+z*O(z^k))^(n-k\2),k,z))
%Y A099528 Cf. A099527.
%K A099528 nonn
%O A099528 0,2
%A A099528 _Paul D. Hanna_, Oct 20 2004
%E A099528 Corrected by _T. D. Noe_, Oct 25 2006