%I #15 Mar 25 2020 07:56:28
%S 1,2,3,5,4,7,6,8,20,9,10,11,21,12,13,22,14,15,23,16,24,17,25,18,19,26,
%T 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,50,42,51,52,43,44,53,45,
%U 46,47,54,48,55,49,56,57,58,59,70,60,71,61,72,62,73,63,74,64,75,65,76,66,77,67,78,68,79,69,200,80
%N Lexicographically earliest sequence of positive distinct integers such that if a(n) steps over a(n) commas to the right, it is met by a term whose leftmost digit is prime.
%H Carole Dubois, <a href="/A333404/b333404.txt">Table of n, a(n) for n = 1..5000</a>
%e a(1) = 1 steps over 1 comma and is met by the prime digit 2;
%e a(2) = 2 steps over 2 commas and is met by the prime digit 5;
%e a(3) = 3 steps over 3 commas and is met by the prime digit 7;
%e a(4) = 5 steps over 5 commas and is met by the prime digit 2 (of "20");
%e a(5) = 4 steps over 4 commas and is met by the same prime digit 2 (of "20"); etc.
%Y Cf. A333406 (same idea, but the leftmost digit of the target is nonprime) and A333324 (leftmost digit is odd).
%K base,nonn
%O 1,2
%A _Eric Angelini_ and _Carole Dubois_, Mar 19 2020