%I
%S 9,29,35,83,85,93,123,173,211,233,249,339,379,419,427,471,473,487,501,
%T 551,575,587,621,625,675,687,763,773,787,801,809,841,915,951,999,1039,
%U 1055,1073,1157,1169,1189,1191,1207,1239,1341,1405,1425,1529,1617,1721
%N Exactly 4 digits from {1,2,3,4,5,6,7,8,9} can precede a(n) to form a lucky number.
%e If a(n) = 1617 then we find only '1'1617, '3'1617, '6'1617 and '7'1617 to be lucky numbers.
%Y Cf. A000959.
%K nonn,base,less
%O 1,1
%A _Patrick De Geest_, May 15 1998
