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#1 |
May 2004
New York City
5·7·112 Posts |
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Find the smallest positive integral value of n
such that the standard decimal representation for both 2n and 3n each contains all ten decimal digits. (What about 4n, 5n, etc. as well?) |
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#2 |
Jan 2005
Transdniestr
503 Posts |
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for 2 and 3, the answer is 70
2^70 is only the 2nd power of 2 to have all 10 digits for powers of 4 and 5, the answer is 34 Funny tangent : 2^64 is the lowest power where if you represent the number in bases:3,5,7,9 or 11 (2 is trivial), all the possible digits for base b can be found in the base b representation of number. |
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#3 | |
Feb 2007
43210 Posts |
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#4 |
Jan 2005
Transdniestr
503 Posts |
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Interesting sequence:
http://www.research.att.com/~njas/sequences/A049363 The nth term is the minimum number such that when represented in bases b=2 to n+1, all possible digits for base b are present. The term they use there is digitally balanced. |
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#5 |
Aug 2005
Brazil
2·181 Posts |
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I don't quite think so. a(5) is 694, but 694 in base 4 doesn't contain the digit 0. It's simply the first pandigital number in base n. If those two sequences were coincidental, it would be something nice, but I think they aren't.
Last fiddled with by fetofs on 2007-06-17 at 15:59 |
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#6 |
Jan 2005
Transdniestr
503 Posts |
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Ugh, I see my problem. It stems from misreading my output:
This is the sequence that matches my earlier description: "Smallest integer containing all digits in all bases from 2 to n" http://www.research.att.com/~njas/se...lish&go=Search Last fiddled with by grandpascorpion on 2007-06-18 at 15:23 |
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