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 A002589 M2234 N0886 #44 Feb 25 2025 23:22:13 %S A002589 3,1,11,43,19,683,2731,331,43691,174763,5419,2796203,4051,87211, %T A002589 3033169,715827883,20857,86171,25781083,22366891,8831418697, %U A002589 2932031007403,18837001,165768537521,4363953127297,6529,28059810762433,48912491,160465489 %N A002589 Largest primitive factor of 2^(2n+1) + 1. %C A002589 Also excludes intrinsic factors which is why a(1)=1 rather than 3. - _Sean A. Irvine_, Apr 20 2014 %D A002589 J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements. %D A002589 M. Kraitchik, Recherches sur la Théorie des Nombres. Gauthiers-Villars, Paris, Vol. 1, 1924, Vol. 2, 1929, see Vol. 2, p. 85. %D A002589 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A002589 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A002589 Max Alekseyev, <a href="/A002589/b002589.txt">Table of n, a(n) for n = 0..563</a> %H A002589 J. Brillhart et al., <a href="http://dx.doi.org/10.1090/conm/022">Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002. %H A002589 S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/cun/index.html">The Cunningham Project</a> %K A002589 nonn %O A002589 0,1 %A A002589 _N. J. A. Sloane_ %E A002589 a(22)-a(472) from _Sean A. Irvine_, Apr 20 2014 %E A002589 a(473)-a(563) from _Max Alekseyev_, Feb 09 2020 - Feb 25 2024