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 A361817 #10 Mar 25 2023 08:19:12
%S A361817 1,2,-2,-16,-10,118,304,-500,-3754,-2488,30866,83716,-135568,-1080972,
%T A361817 -792876,9090484,25788118,-39325156,-335074520,-271779024,2820643842,
%U A361817 8348113120,-11788972644,-107836934448,-96107852032,900943403012,2778574561276,-3596374190416
%N A361817 Expansion of 1/sqrt(1 - 4*x*(1-x)^4).
%F A361817 a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(2*k,k) * binomial(4*k,n-k).
%F A361817 n*a(n) = 2 * ( (2*n-1)*a(n-1) - 4*(2*n-2)*a(n-2) + 6*(2*n-3)*a(n-3) - 4*(2*n-4)*a(n-4) + (2*n-5)*a(n-5) ) for n > 4.
%o A361817 (PARI) my(N=30, x='x+O('x^N)); Vec(1/sqrt(1-4*x*(1-x)^4))
%Y A361817 Cf. A085362, A110170, A162478, A359489, A359758, A360132, A361815, A361816.
%Y A361817 Cf. A361813.
%K A361817 sign
%O A361817 0,2
%A A361817 _Seiichi Manyama_, Mar 25 2023