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 A338816 #11 Nov 14 2020 09:46:21
%S A338816 1,4,28,477,15054,716619,46386636,3829544473,386956394842,
%T A338816 46498297487679,6503866348955704,1041432998153210277,
%U A338816 188367392877258840974
%N A338816 a(0) = 1; for n > 0, a(n) = Sum_{k=0..n-1} prime(a(k)) * prime(a(n-k-1)).
%F A338816 G.f.: 1 + x * (Sum_{n>=0} prime(a(n)) * x^n)^2.
%t A338816 a[0] = 1; a[n_] := a[n] = Sum[Prime[a[k]] Prime[a[n - k - 1]], {k, 0, n - 1}]; Table[a[n], {n, 0, 9}]
%Y A338816 Cf. A000040, A000108, A007097, A014342.
%K A338816 nonn,hard,more
%O A338816 0,2
%A A338816 _Ilya Gutkovskiy_, Nov 10 2020
%E A338816 a(10)-a(11) from _Daniel Suteu_, Nov 10 2020
%E A338816 a(12) from _Jinyuan Wang_, Nov 14 2020