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 A329471 #8 May 29 2022 18:00:35
%S A329471 1,3,12,147,21612,467078547,218162369067631212,
%T A329471 47594819277201331861096436836588947,
%U A329471 2265266822029455509816214491130485582138030749246532017266850242568812
%N A329471 a(n) = a(n-1)^2 + 3 for n >=2 , where a(0) = 1, a(1) = 3.
%C A329471 (a(n)) is a strong divisibility sequence.
%F A329471 a(n) = p(n,0), where p(n,x) is polynomial defined in A329433.
%t A329471 f[x_] := x^2 + 3; u[0, x_] := 1;
%t A329471 u[1, x_] := f[x]; u[n_, x_] := f[u[n - 1, x]]
%t A329471 Table [u[n, x] /. x -> 0, {n, 0, 10}]
%Y A329471 Cf. A329433.
%K A329471 nonn
%O A329471 0,2
%A A329471 _Clark Kimberling_, Dec 31 2019