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A216192 a(n) = Smallest m >= 5 containing no twos when represented in any base from 3 through n. 12
9, 12, 28, 28, 28, 28, 28, 31 (list; graph; refs; listen; history; text; internal format)
OFFSET
3,1
COMMENTS
If a(11) exists, it contains over 3000 digits.
No more terms < 10^154400. Most likely there are no more terms. - Chai Wah Wu, Mar 17 2016
LINKS
EXAMPLE
In base 3, 5=12, 6=20, 7=21, 8=22, 9=100. The first representation containing no twos is that of 9, so a(3)=9.
MATHEMATICA
Table[SelectFirst[Range[5, 10^3], Total@ Map[Function[k, DigitCount[#, k, 2]], Range[3, n]] == 0 &], {n, 3, 20}] /. n_ /; MissingQ@ n -> Nothing (* Michael De Vlieger, Mar 09 2016, Version 10.2 *)
CROSSREFS
Sequence in context: A182877 A114434 A105704 * A340040 A195162 A216297
KEYWORD
nonn,hard,more,base
AUTHOR
Nathan Fox, Mar 12 2013
STATUS
approved

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Last modified April 23 06:58 EDT 2024. Contains 371906 sequences. (Running on oeis4.)