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%I #16 Jun 22 2015 11:41:13
%S 1,2,4,3,5,7,9,6,8,21,11,13,20,22,24,23,15,17,19,31,26,28,40,33,35,37,
%T 39,42,44,46,48,60,62,64,66,68,80,25,51,53,55,57,59,82,84,86,88,200,
%U 201,71,73,75,77,79,91,93,95,97,10,202,204,206,208,220,222,224,99,111,113,115,117,119,131,133,12,226,228,240,242,244,246,248,27,135,137,139,151,110,260,262,264,266,268,29,153,155,157,159,171,173,280,282,284,286,288,400,402,404,406,408,41,175,177,179,191,193,195,197,199,14
%N Underline all odd digits of the sequence. The sequence gives the successive lengths of the underlined/not underlined blocks of digits.
%C A self-describing sequence. The sequence is always extended with the smallest unused integer not leading to a contradiction.
%e (1)(2,4)(3,5,7,9)(6,8,2)(1,11,13)(20,22,24,2)(3,15,17,19,31)... are the first blocks of underlined/not underlined digits; the successive lengths are 1, 2, 4, 3, 5, 7, 9, ... which is the sequence itself.
%K nonn,base
%O 1,2
%A _Eric Angelini_, Mar 07 2014; corrected Jun 22 2015