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A174977 Natural numbers n = n(k) with property that string "2" appears k-times in concatenation Conc(1;n) := 1//2// ... //n (k, n = 1, 2, ...) or 0 if n(k) does not exist. 0
2, 12, 20, 21, 0, 22, 23, 24, 25, 26, 27, 28, 29, 32, 42, 52, 62, 72, 82, 92, 102, 112, 120, 121, 0, 122, 123, 124, 125, 126, 127, 128, 129, 132, 142, 152, 162, 172, 182, 192, 200, 201, 0, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 0, 212, 0, 220, 0, 221, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If a natural n(k) is made of m > 1 digits "2" then (m-1) consecutive values of n(k) = 0, preceding this n(k)

REFERENCES

K. Haase, P. Mauksch: Spass mit Mathe, Urania-Verlag Leipzig, Verlag Dausien Hanau, 2. Auflage 1985

E. I. Ignatjew, Mathematische Spielereien, Urania Verlag Leipzig/Jena/Berlin 1982

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

1//2, n(1) = 2

1//...//21, n(4) = 21

n(5) does not exist, 1//...//22, n(6) = 22

1//...//29, n(13) = 29

1//...//227, n(72) = 227

CROSSREFS

Cf. A174031, A174583.

Sequence in context: A073257 A240905 A303880 * A011532 A277964 A043497

Adjacent sequences:  A174974 A174975 A174976 * A174978 A174979 A174980

KEYWORD

nonn,base

AUTHOR

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 03 2010

STATUS

approved

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Last modified November 14 14:43 EST 2019. Contains 329126 sequences. (Running on oeis4.)