A308406 Lexicographically earliest sequence of distinct terms such that reading one-by-one the central digit of each term is the same as reading one-by-one the successive digits of the sequence itself.

1, 2, 3, 4, 5, 6, 7, 8, 9, 110, 111, 100, 112, 113, 114, 115, 101, 102, 116, 117, 120, 118, 119, 130, 210, 211, 140, 212, 213, 150, 214, 103, 215, 216, 104, 121, 217, 218, 160, 219, 310, 170, 311, 122, 105, 312, 313, 180, 314, 315, 190, 316, 131, 106, 123, 317

Offset

1,2

Comments

All terms of the sequence have an odd number of digits. For terms having only an even number of digits, see the Cross-references section.

Links

Lars Blomberg, Table of n, a(n) for n = 1..10000

Example

The "central digit" of 1 is 1, of course. The central digit of 100 is 0, the central digit of 123 is 2, etc. Reading the successive central digits of the successive terms produces 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 1, 0, 1, 1, 1, 1, 0, 0, sequence, which are exactly the successive digits of the sequence itself.

Crossrefs

Cf. A308407 (the same idea, but with terms having an even number of digits).

Sequence in context: A302656 A077726 A061479 * A028431 A181352 A056143

Adjacent sequences: A308403 A308404 A308405 * A308407 A308408 A308409

Keyword

base,nonn

Author

Eric Angelini, May 25 2019

Extensions

More terms from Lars Blomberg, May 26 2019

Status

approved