%I A100501
%S A100501 1,2,5,8,24,29,84,110,129,176,593,1137,2675,4992
%N A100501 Numbers n such that 3*10^n+7 is prime.
%C A100501 593 and 1137 both give primes. - Joao da Silva (zxawyh66(AT)yahoo.com), 
               Sep 30 2005
%H A100501 Makoto Kamada, <a href="http://homepage2.nifty.com/m_kamada/math/30007.htm">
               Factorizations of 300...007</a>
%H A100501 Sabin Tabirca and Kieran Reynolds, <a href="http://multimedia.ucc.ie/
               Staff/ST/articles/SNJ03_Tabirca1.ps">Lacunary Prime Numbers</a>.
%H A100501 <a href="http://groups.yahoo.com/group/primeform/">Primeform:</a> User 
               group for PFGW & PrimeForm programs
%H A100501 <a href="Sindx_Pri.html#Pri_rep">Index entries for primes involving repunits</
               a>.
%e A100501 (3*10^5)+7 = (3*100000)+7 = 300000+7 = 300007, which is prime.
%t A100501 Do[ If[ PrimeQ[ 3*10^n + 7], Print[ n ]], {n, 0, 20000}]
%Y A100501 Cf. A096774.
%Y A100501 Sequence in context: A137095 A092097 A088144 this_sequence A142869 A086825 
               A093365
%Y A100501 Adjacent sequences: A100498 A100499 A100500 this_sequence A100502 A100503 
               A100504
%K A100501 more,nonn
%O A100501 1,2
%A A100501 Julien Peter Benney (jpbenney(AT)ftml.net), Nov 23 2004
%E A100501 a(12) from Mark Hudson (mrmarkhudson(AT)hotmail.com), Nov 26 2004
%E A100501 a(13 & a(14) from Hugo Pfoertner (hugo(AT)pfoertner.org), Nov 29 2004. 
               The next term is > 20000.