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 A360082 #8 Jan 25 2023 09:08:13 %S A360082 1,1,6,27,134,709,3892,22004,127250,749230,4476386,27071344,165398868, %T A360082 1019405720,6330482488,39571612357,248796862550,1572300095758, %U A360082 9981970108384,63633339713190,407162295120570,2614059813642256,16834457481559076 %N A360082 a(n) = Sum_{k=0..n} binomial(4*k,n-k) * Catalan(k). %F A360082 G.f. A(x) satisfies A(x) = 1/(1 - x * (1+x)^4 * A(x)). %F A360082 G.f.: 2 / (1 + sqrt( 1 - 4*x*(1+x)^4 )). %o A360082 (PARI) a(n) = sum(k=0, n, binomial(4*k, n-k)*binomial(2*k, k)/(k+1)); %o A360082 (PARI) my(N=30, x='x+O('x^N)); Vec(2/(1+sqrt(1-4*x*(1+x)^4))) %Y A360082 Cf. A052709, A073155, A360076, A360083. %Y A360082 Cf. A000108, A099235. %K A360082 nonn %O A360082 0,3 %A A360082 _Seiichi Manyama_, Jan 25 2023