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%I #6 Mar 23 2017 14:36:10
%S 0,1,2,10,20,102,30,3,1020,300,31,40,2030,50,4,3140,200,301,5,60,43,6,
%T 140,2000,3015,7,600,436,11,402,70,100,3010,57,6000,4360,1140,270,8,
%U 1000,310,101,51,760,400,43601,1402,700,810,500,3100,110,15,17,6040,80,9,436010,14027,800,81,10500,13,1001,21,90,151,76040,18
%N The successive digits of the sequence are the same digits that have a nonprime rank in the sequence.
%C The sequence is started with a(1) = 0 and always extended with the smallest integer not yet present and not leading to a contradiction.
%e The first 12 terms are:
%e 0,1,2,10,20,102,30,3,1020,300,31,40
%e Their successive digits are:
%e 0,1,2,1,0,2,0,1,0,2,3,0,3,1,0,2,0,3,0,0,3,1,4,0
%e The nonprime rank digits are here (between parentheses):
%e (0),1,2,(1),0,(2),0,(1),(0),(2),3,(0),3,(1),(0),(2),0,(3),0,(0),(3),(1),4,(0),
%e Erasing the digits not in the parentheses:
%e (0),.,.,(1),.,(2),.,(1),(0),(2),.,(0),.,(1),(0),(2),.,(3),.,(0),(3),(1),.,(0),
%e The surviving digits are:
%e 0,1,2,1,0,2,0,1,0,2,3,0,3,1,0,...
%e Those are indeed the digits of the starting sequence.
%K nonn,base
%O 1,3
%A _Eric Angelini_ and _Jean-Marc Falcoz_, Mar 23 2017
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