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 A371756 #12 Apr 08 2024 04:53:49
%S A371756 1,5,45,456,4863,53383,597052,6765471,77407257,892270250,10346070471,
%T A371756 120542238796,1410040212166,16549315766244,194792566133507,
%U A371756 2298472850258746,27179673132135409,322013956853586970,3821532498419234994,45420775578132979989
%N A371756 a(n) = Sum_{k=0..floor(n/3)} binomial(5*n-2*k,n-3*k).
%F A371756 a(n) = [x^n] 1/((1-x-x^3) * (1-x)^(4*n)).
%F A371756 a(n) ~ 5^(5*n + 5/2) / (99 * sqrt(Pi*n) * 2^(8*n - 1/2)). - _Vaclav Kotesovec_, Apr 05 2024
%F A371756 a(n) = binomial(5*n, n)*hypergeom([1, (1-n)/3, (2-n)/3, -n/3], [(1-5*n)/2, -5*n/2, 1+4*n], -27/4). - _Stefano Spezia_, Apr 06 2024
%o A371756 (PARI) a(n) = sum(k=0, n\3, binomial(5*n-2*k, n-3*k));
%Y A371756 Cf. A144904, A371754, A371755.
%K A371756 nonn
%O A371756 0,2
%A A371756 _Seiichi Manyama_, Apr 05 2024