A342164 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.

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, 41, 44, 28, 47, 50, 41, 52, 56, 50, 56, 56, 56, 50, 56, 53, 72, 42, 75, 54, 80, 80, 76, 83, 80, 85, 92, 90, 80, 54, 99, 94, 99, 86, 99, 98, 99, 108, 99, 108, 99, 108, 99, 126, 99

Offset

0,3

Comments

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

Links

Table of n, a(n) for n=0..69.

Example

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.
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.
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.

Crossrefs

Cf. A125132, A264646, A114308, A263563, A308387

Sequence in context: A135578 A050607 A238368 * A263808 A180477 A271239

Adjacent sequences: A342161 A342162 A342163 * A342165 A342166 A342167

Keyword

nonn,base

Author

Scott R. Shannon, Mar 03 2021

Status

approved