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 A178426 #4 May 23 2024 00:53:34
%S A178426 11,13,145,20737,429981697,184884258895036417,
%T A178426 34182189187166852111368841966125057,
%U A178426 1168422057627266461843148138873451659428421700563161428957815831003137
%N A178426 11 followed by the Fermat numbers A152585.
%C A178426 If a(0)=3, the recursion formula gives A000215.
%F A178426 a(0)=11. a(n)= 2 + Product_{i=0..n-1} a(i).
%t A178426 a[0] := 11;
%t A178426 a[n_] := a[n] = Product[a[i], {i, 0, n - 1}] + 2;
%t A178426 Table[a[n], {n, 0, 10}]
%Y A178426 Cf. A000215, A178427, A178428.
%K A178426 nonn,less
%O A178426 0,1
%A A178426 _Roger L. Bagula_, May 27 2010
%E A178426 Definition simplified by the Assoc. Eds. of the OEIS - May 28 2010