%I A068679
%S A068679 1,3,7,13,31,49,63,81,91,99,103,109,117,123,151,
%T A068679 181,193,213,231,279,319,367,427,459,571,601,613,621,697,721,801,811,
%U A068679 951,987,1113,1117,1131,1261,1821,1831,1939,2101,2149,2211,2517,2611,3151,
               3219,4011,4411,4519,4887,5031,5361,6231,6487,6871,7011,7209,8671,
               9141,9801,10051
%N A068679 Numbers which yield a prime whenever a 1 is inserted anywhere in them 
               (including at the beginning or end).
%C A068679 If R(p) = (10^p -1)/9 is a prime then {(10^(p-1) -1}/9 belongs to this 
               sequence.
%H A068679 C. Caldwell, <a href="http://www.utm.edu/research/primes/">Prime Pages</
               a>
%e A068679 123 belongs to this sequence as the numbers 1123, 1213, 1231 obtained 
               by inserting a 1 in all possible ways are all primes.
%Y A068679 Cf. A068673, A068674, A068677, A069246.
%Y A068679 Sequence in context: A002383 A163418 A161218 this_sequence A006978 A060424 
               A119962
%Y A068679 Adjacent sequences: A068676 A068677 A068678 this_sequence A068680 A068681 
               A068682
%K A068679 base,nonn
%O A068679 1,2
%A A068679 Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 02 2002
%E A068679 More terms from Eli McGowan (ejmcgowa(AT)mail.lakeheadu.ca), Apr 11 2002
%E A068679 More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 16 2002