A171489 - OEIS

A171489

a(n)=k is the smallest exponent k such that at least 4 equal decimal digits "n n n n" appear in the decimal representation of 2^k (n=0,1,...,9).

377, 313, 314, 219, 192, 41, 220, 181, 180, 421

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OFFSET

0,1

REFERENCES

Theo Kempermann, Zahlentheoretische Kostproben, Harri Deutsch, 2. aktualisierte Auflage 2005

Hugo Steinhaus, 100 neue Aufgaben: Elementare Mathematik, Urania Verlag Leipzig-Jena-Berlin 1973

LINKS

EXAMPLE

0: 2^377 = 307828173409331868845930000782371982852185463050511302093346042220669701339821957901673955116288403443801781174272

1: 2^313 = 16687398718132110018711107079449625895333629080911349765211262561111091607661254297054391304192

2: 2^314 = 33374797436264220037422214158899251790667258161822699530422525122222183215322508594108782608384

3: 2^219 = 842498333348457493583344221469363458551160763204392890034487820288

4: 2^192 = 6277101735386680763835789423207666416102355444464034512896

5: 2^41 = 2199023255552

6: 2^220 = 1684996666696914987166688442938726917102321526408785780068975640576

7: 2^181 = 3064991081731777716716694054300618367237478244367204352

8: 2^180 = 1532495540865888858358347027150309183618739122183602176

9: 2^421 = 5415370496329716522614090203404460358274291162843391748379842930887932241807862544999950011922147613471467208908991351228465152

Theo Kempermann, Zahlentheoretische Kostproben, Harri Deutsch, 2. aktualisierte Auflage 2005

CROSSREFS

KEYWORD

fini,full,nonn,base

AUTHOR

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Dec 10 2009

STATUS

approved