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%I #15 Mar 10 2020 09:31:31
%S 2,3,5,1,7,8,22,11,20,15,21,14,23,25,26,27,29,31,32,19,35,36,37,39,40,
%T 41,49,51,52,53,54,55,57,58,59,60,61,63,70,71,73,75,76,77,78,79,81,82,
%U 83,85,90,92,94,98,105,109,200,115,201,114,122,123,125,126
%N A self-describing sequence: when the sequence is read as a string of digits, a(n) says the position of the digits that are prime.
%C Digits in position a(n) are prime, namely 2, 3, 5 or 7. Any step chooses the minimum integer not yet present in the sequence and not leading to a contradiction.
%H <a href="/index/Sa#swys">Index to sequences related to say what you see</a>
%e The sequence cannot start with 1 because the first digit, 1 itself, is not prime. Then let us put 2. The next digit must be prime: 3. Even the third must be prime: 5. No specific indications for the fourth digit. We can choose 1 because the first digit, 2, is prime. The fifth must be prime: 7. And so on.
%Y Cf. A114315 and A121053.
%K nonn,base
%O 1,1
%A _Paolo P. Lava_, Feb 15 2012
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