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 A006485 M2912 #34 Apr 03 2023 16:14:48
%S A006485 3,11,171,43691,2863311531,12297829382473034411,
%T A006485 226854911280625642308916404954512140971,
%U A006485 77194726158210796949047323339125271902179989777093709359638389338608753093291
%N A006485 a(n) = (2^(2^n + 1) + 1)/3.
%D A006485 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006485 Delbert L. Johnson, <a href="/A006485/b006485.txt">Table of n, a(n) for n = 1..11</a>
%H A006485 D. S. Kluk and N. J. A. Sloane, <a href="/A002050/a002050_3.pdf">Correspondence, 1979</a>.
%F A006485 a(n) = A001045(2^n+1) = (3*a(n-1)^2 + 1)/2 - a(n-1). - _Michael Somos_, Mar 30 2020
%F A006485 a(n) = A070969(n)/3. - _Alois P. Heinz_, Mar 28 2023
%t A006485 lst={};Do[AppendTo[lst, (2^(2^n+1)+1)/3], {n, 9}];lst (* _Vladimir Joseph Stephan Orlovsky_, Sep 19 2008 *)
%t A006485 Table[(1+2^(2^n+1))/3,{n,10}] (* _Harvey P. Dale_, Apr 03 2023 *)
%o A006485 (PARI) {a(n) = if(n > 0, (2^(2^n + 1) + 1)/3, 0)}; /* _Michael Somos_, Mar 30 2020 */
%Y A006485 Cf. A001045, A070969.
%K A006485 nonn
%O A006485 1,1
%A A006485 Dennis S. Kluk (mathemagician(AT)ameritech.net)