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 A229768 #12 Jun 07 2022 15:20:49
%S A229768 13,41,29,109,2113,157,1321,26317,525313,1429,1657,268501,279073,
%T A229768 536903681,49477,4327489,7416361,231769777,21841,43249589,500177,
%U A229768 29247661,7484047069,19707683773,1326700741,586477649,3630105520141,275415303169,104399276341
%N A229768 Largest prime factor of 2^(2*n+1)+2^(n+1)+1.
%C A229768 2^(2*n+1)+2^(n+1)+1 is a factor of 4^(2*n+1)+1.
%H A229768 Daniel Suteu, <a href="/A229768/b229768.txt">Table of n, a(n) for n = 1..547</a>
%e A229768 For n=10, 2^(2*n+1)+2^(n+1)+1 = 2099201 = 13*113*1429, so a(10)=1429.
%t A229768 Table[FactorInteger[2^(2n+1)+2^(n+1)+1][[-1,1]],{n,30}] (* _Harvey P. Dale_, Nov 03 2017 *)
%o A229768 (PARI) a(n) = {f=factor(2^(2*n+1)+2^(n+1)+1); f[matsize(f)[1],1]}
%Y A229768 Cf. A085601, A207262, A229747, A229767.
%K A229768 nonn
%O A229768 1,1
%A A229768 _Colin Barker_, Sep 29 2013