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 A351438 #5 Feb 16 2022 04:11:54
%S A351438 1,1,1,4,11,29,85,281,1003,3764,14811,61327,267153,1219497,5807473,
%T A351438 28763988,147898511,788330533,4349414397,24799271517,145904796179,
%U A351438 884577652276,5519858796807,35415056743815,233393746525705,1578437838849645,10945142365689985,77752626344174676
%N A351438 G.f. A(x) satisfies: A(x) = 1 + x + x^2 * A(x/(1 - x)) / (1 - x)^3.
%F A351438 a(0) = a(1) = 1; a(n) = Sum_{k=0..n-2} binomial(n,k+2) * a(k).
%t A351438 nmax = 27; A[_] = 0; Do[A[x_] = 1 + x + x^2 A[x/(1 - x)]/(1 - x)^3 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
%t A351438 a[0] = a[1] = 1; a[n_] := a[n] = Sum[Binomial[n, k + 2] a[k], {k, 0, n - 2}]; Table[a[n], {n, 0, 27}]
%Y A351438 Cf. A007476, A045501, A351437.
%K A351438 nonn
%O A351438 0,4
%A A351438 _Ilya Gutkovskiy_, Feb 11 2022