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%I #11 Dec 01 2019 23:13:23
%S 1,2,3,10,4,12,5,13,6,14,7,15,8,16,9,17,21,20,18,31,22,19,31,23,100,
%T 102,103,104,105,106,107,108,109,120,122,123,124,125,126,127,128,129,
%U 130,132,133,134,135,136,137,138,139,140,142,143,144,145,146,147,148,149,150
%N Lexicographically first sequence (with no duplicate term) where all the digits "1" are separated by two digits.
%C The sequence is started with a(1)=1 and always extended with the smallest integer not yet used that does not lead to a contradiction.
%e To match the infinite digit-pattern 1..1..1..1..1..1.. (etc.) one must use the integer 10 after the third term (which is 3), then use the integer 4, then use the integer 12 (as 11 is forbidden: no integer with consecutive 1's is allowed), etc.
%K nonn,base
%O 1,2
%A _Eric Angelini_, Aug 18 2016