%I #22 Apr 18 2021 02:15:11
%S 2,20,1,6,21,9,22,10,15,23,19,222,220,25,27,29,32,35,200,40,201,45,
%T 202,47,52,203,51,59,204,64,205,69,206,74,207,79,208,84,209,89,210,94,
%U 211,99,212,101,108,213,114,214,120,215,118,127,132,216,131,141,217
%N List the positions of all digits 2 in the concatenation of all terms, not necessarily in order. This is the lexicographically earliest such sequence.
%C See A210415 for comments, links, and code.
%C See A098670 for a variant with increasing terms. - _M. F. Hasler_, Oct 08 2013
%H Danny Rorabaugh, <a href="/A210416/b210416.txt">Table of n, a(n) for n = 1..1000</a>
%e The sequence starts with 2: the second digit is equal to 2. In the second position we cannot write only 2 because the first number is already 2. So we use the minimum number greater than 2 and beginning with digit 2, i.e., 20. In the third position we can write 1 because the digit in the first position is 2. And so on.
%Y Cf. A098670, A210414-A210423.
%K nonn,base
%O 1,1
%A _Paolo P. Lava_, Mar 26 2012