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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

Table of n, a(n) for n=3..10.

Nathan Fox, Maple Program to compute a(n)

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

Cf. A216194, A270037, A270038, A270039, A270040, A270041, A270042, A270043, A270044, A270045.

Sequence in context: A182877 A114434 A105704 * A195162 A216297 A024312

Adjacent sequences:  A216189 A216190 A216191 * A216193 A216194 A216195

KEYWORD

nonn,hard,more,base

AUTHOR

Nathan Fox, Mar 12 2013

STATUS

approved

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Last modified October 17 04:09 EDT 2019. Contains 328106 sequences. (Running on oeis4.)