A342164 - OEIS

%I #7 Mar 07 2021 14:47:40

%S 0,1,2,3,4,5,6,7,8,9,10,11,12,15,17,19,16,23,18,27,30,27,22,27,24,39,

%T 41,44,28,47,50,41,52,56,50,56,56,56,50,56,53,72,42,75,54,80,80,76,83,

%U 80,85,92,90,80,54,99,94,99,86,99,98,99,108,99,108,99,108,99,126,99

%N A self-describing sequence: start with 0, then for each digit in each successive term, starting from the first term, append to the sequence its most recent position in the string formed by the concatenation of all previous terms.

%C After the leading zero taking the a(n)-th digit of the sequence returns the digits of the sequence.

%e The second term is 1 as the 0 in the first term appears as the first digit in the sequence. Likewise the third term is 2 as the 1 in the second term is the second digit of the sequence, and so on to the eleventh term.

%e As the eleventh term is 10 and has two digits, the twelfth and thirteenth terms give the most recent position of a 1 and 0 in the sequence, and they appear at the eleventh and twelfth position.

%e As the twelfth term is 11, the fourteenth and fifteenth terms give the most recent position of the two 1's. The last 1 appears at the fifteenth position, and after appending 15, which contains a 1, the most recent 1 now appears at the seventeenth position.

%Y Cf. A125132, A264646, A114308, A263563, A308387

%K nonn,base

%O 0,3

%A _Scott R. Shannon_, Mar 03 2021