A270040 a(n) = Smallest m >= 9 containing no fours when represented in any base from 5 through n.

10, 11, 12, 13, 15, 15, 17, 17, 66, 75, 75, 86, 86, 90, 138, 138, 138, 138, 138, 138, 138, 138, 138, 182, 182, 182, 182, 182, 182, 182, 182, 182, 185, 781817578165, 781817578165, 7826560751018861596150680

Offset

5,1

Comments

It remains to be determined if the sequence is finite.

These numbers are not very Foury, at least not initially. (See A268236.)

Links

Nathan Fox, Table of n, a(n) for n = 5..59

Mathematica

Table[SelectFirst[Range[9, 10^3], Total@ Map[Function[k, DigitCount[#, k, 4]], Range[5, n]] == 0 &], {n, 5, 60}] /. n_ /; MissingQ@ n -> Nothing (* Michael De Vlieger, Mar 10 2016, Version 10.2 *)

Crossrefs

Cf. A268236, A268237, A270030, A270037, A270038, A216192, A270039, A270041, A270042, A270043, A270044, A270045.

Sequence in context: A008707 A089951 A058945 * A339093 A072554 A138582

Adjacent sequences: A270037 A270038 A270039 * A270041 A270042 A270043

Keyword

nonn,base

Author

Nathan Fox, Mar 09 2016

Status

approved