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 A062013 #20 Jun 07 2021 15:24:03
%S A062013 3,10,101,10202,104080805,10832813969448026,
%T A062013 117349858496668297583751115296677,
%U A062013 13770989289188072635789270799554901596999795308252284177727242330
%N A062013 a(1) = 3, a(n) = a(n-1)^2 + 1.
%C A062013 Define f(n, c) := x - Sum_{k>=0} A088674(k)/(2*x)^(2*k+1) where x = c^(2^n). Then a(n) = f(n, 1.78050350...). - _Michael Somos_, Jun 07 2021
%H A062013 Harry J. Smith, <a href="/A062013/b062013.txt">Table of n, a(n) for n = 1..11</a>
%F A062013 a(n) ~ c^(2^n), where c = 1.78050350352842911667602268320603615359... - _Vaclav Kotesovec_, Sep 20 2013
%e A062013 a(4) = a(3)^2 +1 = 101^2 +1 =10202
%t A062013 NestList[#^2+1&,3,10] (* _Harvey P. Dale_, Feb 21 2013 *)
%t A062013 a[ n_] := If[n < 2, 3 Boole[n == 1], A062013[n - 1]^2 + 1]; (* _Michael Somos_, Jun 07 2021 *)
%o A062013 (PARI) { for (n=1, 11, if (n==1, a=3, a=a^2 + 1); write("b062013.txt", n, " ", a) ) } [_Harry J. Smith_, Jul 29 2009]
%Y A062013 Cf. A003095, A088674.
%K A062013 nonn
%O A062013 1,1
%A A062013 _Amarnath Murthy_, Jun 01 2001
%E A062013 More terms from _Jason Earls_, Jun 02 2001
%E A062013 Offset changed from 0,1 to 1,1 by _Harry J. Smith_, Jul 29 2009
%E A062013 Typo in a(8) corrected by _N. J. A. Sloane_, Aug 31 2009 using the b-file.