%I #4 Dec 05 2013 19:56:38
%S 7,17,0,1117,11117,0,1111711,11111117,0,1117111111,17111111111,0,
%T 1111171111111,0,0,0,11111111111111171,0,1111111111111111171,
%U 11111111111111117111,0,1111111111111111111711,11111111111111111111117
%N Least n-digit prime using digit 7 once and rest all 1, or 0 if no such prime exists.
%C a(3n) = 0.
%e a(5) = 11117.
%Y Cf. A090536, A090537, A090538.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Dec 08 2003
%E More terms from _David Wasserman_, Jan 03 2006