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%I #7 Sep 24 2018 16:53:14
%S 1,3,4,6,9,10,12,13,14,15,18,19,21,24,27,30,31,32,33,36,37,39,40,41,
%T 42,43,44,45,46,47,48,51,54,57,58,59,60,63,64,66,69,72,75,78,81,84,87,
%U 90,93,94,95,96,97,98,99,100,101,102,105,108,111,112,113,114,117,118,120
%N Self-describing sequence. The n-th integer of the sequence indicates how many integers of the sequence are strictly < 3n.
%C Terms computed by Gilles Sadowski. In building step by step the sequence one has sometimes the choice for an integer. If so take the smallest available one.
%C Is this the same sequence as A080710? - _Andrew S. Plewe_, May 08 2007
%e a(7)=12 because there are 12 integers in the sequence which are strictly < 21 (they are 1,3,4,6,9,10,12,13,14,15,18,19).
%K base,easy,nonn
%O 1,2
%A _Eric Angelini_, Feb 01 2006