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 A358496 #9 Dec 26 2023 16:50:07
%S A358496 1,2,3,7,24,176,2623,79479,5141566,669156932,178757299486,
%T A358496 104033138190939,125893536876304530,320091464865316176891,
%U A358496 1828276720220263211454403,22393381352339181425954204921,582288411818399885839904060337943,34678571156322738984042119670750665153
%N A358496 a(n) = Sum_{k=0..n} binomial(binomial(n, k), k).
%F A358496 Limit_{n->infinity} a(n)^(1/n^2) = r^(r^2/(1-2*r)) = 1.533628065110458582..., where r = A220359 = 0.70350607643066243096929661621777... is the real root of the equation (1-r)^(2*r-1) = r^(2*r).
%t A358496 Table[Sum[Binomial[Binomial[n, k], k], {k, 0, n}], {n, 0, 20}]
%o A358496 (PARI) a(n) = sum(k=0, n, binomial(binomial(n, k), k)); \\ _Michel Marcus_, Nov 19 2022
%Y A358496 Cf. A167008, A220359, A357871, A358495.
%K A358496 nonn
%O A358496 0,2
%A A358496 _Vaclav Kotesovec_, Nov 19 2022