%I A088275
%S A088275 1,2,3,4,9,18,22,45,49,56,69,146,202,272,2730,2841,4562,31810,43186,
%T A088275 48109
%N A088275 Numbers n such that 10^n + 9 is prime.
%C A088275 No others less than 9000. - Julien Peter Benney (jpbenney(AT)ftml.net), 
               Jan 15 2005
%C A088275 No others less than 39254. - Dirk Augustin, Oct 24 2006
%C A088275 2730, 2841 and 4562 all give primes. - Joao da Silva (zxawyh66(AT)yahoo.com), 
               Sep 30 2005
%H A088275 Makoto Kamada, <a href="http://homepage2.nifty.com/m_kamada/math/10009.htm">
               Factorizations of 100...009</a>.
%H A088275 Sabin Tabiraca and Kieran Reynolds, <a href="http://multimedia.ucc.ie/
               Staff/ST/articles/SNJ03_Tabirca1.ps">Lacunary Prime Numbers</a>.
%H A088275 <a href="Sindx_Pri.html#Pri_rep">Index entries for primes involving repunits</
               a>.
%e A088275 4 is a member since 10^4 + 9 = 10009 is a prime.
%t A088275 Do[ If[ PrimeQ[ 10^n + 9], Print[n]], {n, 0, 10000}] (from Robert G. 
               Wilson v Dec 16 2004)
%Y A088275 Cf. A049054, A088274.
%Y A088275 Sequence in context: A119721 A098969 A145027 this_sequence A014281 A086865 
               A122534
%Y A088275 Adjacent sequences: A088272 A088273 A088274 this_sequence A088276 A088277 
               A088278
%K A088275 nonn
%O A088275 1,2
%A A088275 Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 28 2003
%E A088275 a(8)-a(16) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 10 
               2003
%E A088275 a(17) from Julien Peter Benney (jpbenney(AT)ftml.net), Jan 15 2005
%E A088275 a(18) (a PRP) found by Dirk Augustin, Oct 16 2006
%E A088275 Two more terms (probable primes), found with WinPFGW. No others less 
               than 60400. - Jason Earls (zevi_35711(AT)yahoo.com), Dec 22 2007