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 A371775 #8 Apr 06 2024 10:05:17
%S A371775 1,5,36,287,2396,20539,179125,1581282,14085997,126357958,1139825257,
%T A371775 10328791996,93951594230,857328996139,7844767641718,71951952863375,
%U A371775 661311093597592,6089245462608316,56160004711457917,518707264791838694,4797177987838607105
%N A371775 a(n) = Sum_{k=0..floor(n/3)} binomial(4*n-k+1,n-3*k).
%F A371775 a(n) = [x^n] 1/(((1-x)^2-x^3) * (1-x)^(3*n)).
%o A371775 (PARI) a(n) = sum(k=0, n\3, binomial(4*n-k+1, n-3*k));
%Y A371775 Cf. A371773, A371774, A371776.
%K A371775 nonn
%O A371775 0,2
%A A371775 _Seiichi Manyama_, Apr 05 2024