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 A351437 #6 Feb 16 2022 04:12:16
%S A351437 1,1,1,3,7,17,47,145,481,1691,6295,24805,103095,449805,2052081,
%T A351437 9762699,48334855,248568321,1325297879,7312927481,41694974649,
%U A351437 245288605059,1487041552343,9279329735685,59537092965663,392371097100373,2653606218921673,18400405626141667,130712743774279015
%N A351437 G.f. A(x) satisfies: A(x) = 1 + x + x^2 * A(x/(1 - x)) / (1 - x)^2.
%F A351437 a(0) = a(1) = 1; a(n) = Sum_{k=0..n-2} binomial(n-1,k+1) * a(k).
%t A351437 nmax = 28; A[_] = 0; Do[A[x_] = 1 + x + x^2 A[x/(1 - x)]/(1 - x)^2 + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
%t A351437 a[0] = a[1] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, k + 1] a[k], {k, 0, n - 2}]; Table[a[n], {n, 0, 28}]
%Y A351437 Cf. A007476, A040027, A351438.
%K A351437 nonn
%O A351437 0,4
%A A351437 _Ilya Gutkovskiy_, Feb 11 2022