%I A003021 M2007
%S A003021 2,11,101,13,137,9091,9901,909091,5882353,52579,27961,8779,99990001,
%T A003021 1058313049,121499449,9091,69857,21993833369,999999000001,
%U A003021 909090909090909091,5964848081,909091,1056689261,549797184491917
%N A003021 Largest factor of 10^n + 1.
%D A003021 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A003021 J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, 
               Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and 
               later supplements.
%H A003021 J. Brillhart et al., <a href="http://www.ams.org/online_bks/conm22/">
               Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, 
               Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
%H A003021 T. Granlund, <a href="http://www.swox.com/gmp/fac10p.txt">Factors of 
               10^n + 1</a>
%H A003021 S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/
               cun/index.html">The Cunningham Project</a>
%o A003021 (PARI) for(n=0,22,print(factor(10^n+1)))
%Y A003021 Sequence in context: A157715 A001271 A038371 this_sequence A097463 A083394 
               A087988
%Y A003021 Adjacent sequences: A003018 A003019 A003020 this_sequence A003022 A003023 
               A003024
%K A003021 nonn,easy
%O A003021 0,1
%A A003021 N. J. A. Sloane (njas(AT)research.att.com).
%E A003021 More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jul 11 2001