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 A031440 #24 Sep 02 2023 17:00:09 %S A031440 3,7,47,2207,4481,26111,189017,67271,11815633,606737,708641,354023, %T A031440 125332284527,51939720282500417,18062107820423,1376080289340623571113, %U A031440 4012316132900773615751,983669740542169,4443427285129103,19744046038229790810567377584607,4300749014896245437702886338812998834884967953,41572359968343362282287450730112204489086145685200294134959430572332688727999 %N A031440 a(0) = 3; for n > 0, a(n) is the greatest prime factor of a(n-1)^2 - 2. %C A031440 Is this sequence unbounded? [_Charles R Greathouse IV_, Dec 29 2011] %H A031440 Dennis Langdeau, <a href="/A031440/b031440.txt">Table of n, a(n) for n = 0..23</a> %t A031440 NestList[FactorInteger[#^2-2][[-1,1]]&,3,22] (* _Harvey P. Dale_, Jan 10 2013 *) %K A031440 nonn,nice %O A031440 0,1 %A A031440 _Yasutoshi Kohmoto_ %E A031440 More terms from Dennis Langdeau (dlangdea(AT)sfu.ca), Jun 26 2006