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 A368046 #9 Dec 10 2023 16:58:22
%S A368046 0,3,21,76,200,435,833,1456,2376,3675,5445,7788,10816,14651,19425,
%T A368046 25280,32368,40851,50901,62700,76440,92323,110561,131376,155000,
%U A368046 181675,211653,245196,282576,324075,369985,420608,476256,537251
%N A368046 a(n) = ((n + 1)^2 * (5*n + 4)*n) / 12.
%H A368046 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5,-10,10,-5,1).
%F A368046 a(n) = Sum_{k=0..n} A368045(k).
%F A368046 G.f.: x*(3 + 6*x + x^2)/(1 - x)^5. - _Stefano Spezia_, Dec 10 2023
%t A368046 A368046[n_]:=((n+1)^2(5n+4)n)/12;Array[A368046,50,0] (* or *)
%t A368046 LinearRecurrence[{5,-10,10,-5,1},{0,3,21,76,200},50] (* _Paolo Xausa_, Dec 10 2023 *)
%Y A368046 Cf. A368045.
%K A368046 nonn,easy
%O A368046 0,2
%A A368046 _Peter Luschny_, Dec 09 2023