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 A368489 #9 Dec 27 2023 07:52:19
%S A368489 1,3,31,643,20421,873806,46994011,3042431715,230249448841,
%T A368489 19940350062394,1944516598602711,210829412453667998,
%U A368489 25156743053019602701,3275876521195372322892,462262670054775645538099,70264375447526610838701091
%N A368489 a(n) = Sum_{k=0..n} n^k * binomial(k+n,k).
%F A368489 a(n) = [x^n] 1/((1-x) * (1-n*x)^(n+1)).
%F A368489 a(n) ~ 4^n * n^(n - 1/2) / sqrt(Pi). - _Vaclav Kotesovec_, Dec 27 2023
%o A368489 (PARI) a(n) = sum(k=0, n, n^k*binomial(k+n, k));
%Y A368489 Cf. A001700, A026641, A368488.
%K A368489 nonn,easy
%O A368489 0,2
%A A368489 _Seiichi Manyama_, Dec 27 2023