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 A348875 #11 Nov 03 2021 04:29:04
%S A348875 1,2,8,56,656,13184,477248,32524928,4295916032,1117098857984,
%T A348875 576442191401984,592587279827787776,1215991461595100598272,
%U A348875 4985567391504232291377152,40861715233637664786276712448,669641809249948891254213657460736,21945501536426419427607885034600595456
%N A348875 G.f. A(x) satisfies: A(x) = 1 / (1 - x - x * A(2*x)).
%F A348875 a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} 2^k * a(k) * a(n-k-1).
%F A348875 a(n) ~ c * 2^(n*(n-1)/2), where c = 1/(A048651 * A083864) = 2*Product_{j>=1} (2^j+1)/(2^j-1) = 16.51197587155650013108828169886454625305400323357646... - _Vaclav Kotesovec_, Nov 03 2021
%t A348875 nmax = 16; A[_] = 0; Do[A[x_] = 1/(1 - x - x A[2 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
%t A348875 a[0] = 1; a[n_] := a[n] = a[n - 1] + Sum[2^k a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 16}]
%Y A348875 Cf. A006318, A015083, A348876, A348877.
%K A348875 nonn
%O A348875 0,2
%A A348875 _Ilya Gutkovskiy_, Nov 02 2021