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%I #8 Feb 20 2019 16:04:26
%S 2,3,4,5,6,7,8,9,11,12,14,1,16,10,17,20,13,22,15,23,18,19,21,26,24,25,
%T 27,29,28,30,32,34,31,35,33,36,37,38,39,40,41,42,43,44,47,45,46,48,49,
%U 51,50,53,52,54,55,57,56,58,59,60,62,63,61,66,65,69,64,70,67,68,71,72,73,74,75,76,78,77,79,80,81,82,83,84,85
%N Lexicographically earliest sequence of different terms starting with a(1) = 2 such that the n-th digit of the sequence, placed after a(n) and then concatenated, produces a composite number.
%C The sequence is a permutation of the numbers > 0.
%H Jean-Marc Falcoz, <a href="/A324281/b324281.txt">Table of n, a(n) for n = 1..10009</a>
%e The 1st digit of the sequence (2) concatenated to the 1st term = 22 (composite);
%e the 2nd digit of the sequence (3) concatenated to the 2nd term = 33 (composite);
%e the 3rd digit of the sequence (4) concatenated to the 3rd term = 44 (composite);
%e the 4th digit of the sequence (5) concatenated to the 4th term = 55 (composite);
%e the 5th digit of the sequence (6) concatenated to the 5th term = 66 (composite);
%e the 6th digit of the sequence (7) concatenated to the 6th term = 77 (composite);
%e the 7th digit of the sequence (8) concatenated to the 7th term = 88 (composite);
%e the 8th digit of the sequence (9) concatenated to the 8th term = 99 (composite);
%e the 9th digit of the sequence (1) concatenated to the 9th term = 111 (composite);
%e the 10th digit of the sequence (1) concatenated to the 10th term = 121 (composite);
%e the 11th digit of the sequence (1) concatenated to the 11th term = 141 (composite);
%e the 12th digit of the sequence (2) concatenated to the 12th term = 12 (composite);
%e the 13th digit of the sequence (1) concatenated to the 13th term = 161 (composite);
%e etc.
%Y Cf. A306311, A306321, A324279, A324280 and A324282 where the same idea is used.
%K base,nonn
%O 1,1
%A _Eric Angelini_ and _Jean-Marc Falcoz_, Feb 20 2019
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