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 A299502 #9 Jan 30 2020 21:29:18
%S A299502 1,3,13,59,277,1347,6685,33675,171493,880531,4550125,23633627,
%T A299502 123272117,645247715,3387538621,17830213931,94058445445,497152260915,
%U A299502 2632288649869,13958805204603,74124967884373,394115410904195,2097849420888925,11178238250228427
%N A299502 Expansion of (1 - 6*x + x^2 + 8*x^3 + 16*x^4)^(-1/2).
%C A299502 See A299500 for a family of related polynomials.
%F A299502 a(n) = Sum_{k=0..n} 2^k*binomial(n,k)*hypergeom([-k,k-n,k-n], [1,-n], 2).
%F A299502 D-finite with recurrence: (16*n-32)*a(n-4) + (8*n-12)*a(n-3) + (n-1)*a(n-2) + (3-6*n)*a(n-1) + n*a(n) = 0.
%p A299502 a := n -> add(2^k*binomial(n,k)*hypergeom([-k,k-n,k-n], [1,-n], 2), k=0..n):
%p A299502 seq(simplify(a(n)), n=0..28);
%t A299502 CoefficientList[Series[(1 - 6x + x^2 + 8x^3 + 16x^4)^(-1/2), {x, 0, 23}], x]
%Y A299502 Cf. A298611, A299500.
%K A299502 nonn
%O A299502 0,2
%A A299502 _Peter Luschny_, Feb 15 2018