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A171242 a(n)=k is the smallest exponent k such that at least 3 equal decimal digits "n n n" appear in the decimal representation of 2^k (n=0,1,...,9). 6
242, 42, 43, 83, 44, 41, 157, 24, 39, 50 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

E. I. Ignatjew, Mathematische Spielereien, Urania Verlag Leipzig-Jena-Berlin, 2. Auflage 1982

Helmut Kracke, Mathe-musische Knobelisken, Duemmler Bonn, 2. Auflage 1983

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

n=0: 2^242 = 7067388259113537318333190002971674063309935587502475832486424805170479104

n=1: 2^42 = 4398046511104

n=2: 2^43 = 8796093022208

n=3: 2^83 = 9671406556917033397649408

n=4: 2^44 = 17592186044416

n=5: 2^41 = 2199023255552

n=6: 2^157 = 182687704666362864775460604089535377456991567872

n=7: 2^24 = 16777216

n=8: 2^39 = 549755813888

n=9: 2^50 = 1125899906842624

CROSSREFS

Cf. A000079, A018802, A171132.

Sequence in context: A183891 A120377 A321821 * A259092 A060110 A113468

Adjacent sequences:  A171239 A171240 A171241 * A171243 A171244 A171245

KEYWORD

fini,full,nonn,base

AUTHOR

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Dec 06 2009

STATUS

approved

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Last modified February 28 09:24 EST 2021. Contains 341695 sequences. (Running on oeis4.)