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A106003 Keep only the middle digit of each integer and concatenate them. The result is the concatenation of all integers of the sequence. 1
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 110, 111, 200, 210, 211, 212, 220, 300, 400, 420, 510, 600, 620, 710, 711, 720, 810, 820, 822, 823, 900, 930, 10000, 10001, 10400, 11000, 11001, 11400, 12200, 13000, 13500, 14100, 15000, 15600, 16000, 16001, 16600, 17200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Could one say this is kind of fractal?

The definition seems to be the following: all terms have an odd number of digits, and are strictly increasing. Now delete all except the middle digits of each term. The result is the succession of digits of all the terms. We take the lexicographically earliest sequence satisfying these conditions. - N. J. A. Sloane, Aug 09 2012

LINKS

Table of n, a(n) for n=0..47.

CROSSREFS

Cf. A106004.

Sequence in context: A028431 A181352 A056143 * A283868 A087995 A082232

Adjacent sequences:  A106000 A106001 A106002 * A106004 A106005 A106006

KEYWORD

base,easy,nonn

AUTHOR

Eric Angelini, Apr 29 2005

STATUS

approved

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Last modified November 12 16:50 EST 2018. Contains 317116 sequences. (Running on oeis4.)