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 A371825 #8 Apr 07 2024 17:43:53
%S A371825 1,3,18,146,1510,19302,296520,5339924,110447046,2581169510,
%T A371825 67274981356,1934941601628,60878718397276,2080009638726684,
%U A371825 76694241037743300,3035502492679964520,128364744764608411718,5776084128332328033798,275565308510875579650348
%N A371825 a(n) = Sum_{k=0..n} n^k * binomial(2*n,n-k).
%F A371825 a(n) = [x^n] 1/((1-(n+1)*x) * (1-x)^n).
%F A371825 a(n) ~ exp(2) * n^n. - _Vaclav Kotesovec_, Apr 07 2024
%o A371825 (PARI) a(n) = sum(k=0, n, n^k*binomial(2*n, n-k));
%Y A371825 Cf. A371826, A371827.
%K A371825 nonn
%O A371825 0,2
%A A371825 _Seiichi Manyama_, Apr 07 2024