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 A371890 #7 Apr 11 2024 10:10:22
%S A371890 1,1,2,1,-4,0,37,16,-313,-214,3005,2943,-30391,-39432,318606,522863,
%T A371890 -3418205,-6889626,37219105,90415336,-408758113,-1183054415,
%U A371890 4505089166,15442590040,-49599878555,-201138280510,542949788652,2614332298108,-5877502079248
%N A371890 G.f. A(x) satisfies A(x) = 1 - x/A(x)^3 * (1 - A(x) - A(x)^4).
%F A371890 a(n) = (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(n-4*k,n-k-1) for n > 0.
%o A371890 (PARI) a(n) = if(n==0, 1, sum(k=0, n, binomial(n, k)*binomial(n-4*k, n-k-1))/n);
%Y A371890 Cf. A349331, A364748, A367724, A371891.
%K A371890 sign
%O A371890 0,3
%A A371890 _Seiichi Manyama_, Apr 11 2024