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 A366978 #11 Sep 19 2024 08:53:36
%S A366978 1,5,17,64,220,839,3061,11684,44126,169432,648589,2505411,9670165,
%T A366978 37497431,145502481,566076182,2204451031,8599761208,33581164151,
%U A366978 131296796355,513812162117,2012709456997,7890502860027,30958303856804,121549519502347,477555096290870,1877411492125154
%N A366978 a(n) = Sum_{j=1..n} binomial(floor(n/j)+n,n+1).
%F A366978 a(n) = Sum_{j=1..n} binomial(j+n-1,n)*floor(n/j).
%F A366978 a(n) ~ 4^n / sqrt(Pi*n). - _Vaclav Kotesovec_, Sep 19 2024
%t A366978 Table[Sum[Binomial[j+n-1,n]Floor[n/j],{j,n}],{n,30}] (* _Harvey P. Dale_, Jul 19 2024 *)
%o A366978 (Python)
%o A366978 from math import isqrt, comb
%o A366978 def A366978(n): return (-(s:=isqrt(n))**2*comb(s+n,n)+sum((q:=n//j)*((n+1)*comb(j+n-1,n)+comb(q+n,n)) for j in range(1,s+1)))//(n+1)
%Y A366978 Superdiagonal of array in A366977.
%K A366978 nonn
%O A366978 1,2
%A A366978 _Chai Wah Wu_, Oct 30 2023