A270043 a(n) = Smallest m >= 15 containing no sevens when represented in any base from 8 through n.

16, 17, 18, 19, 20, 21, 22, 24, 24, 26, 26, 28, 28, 30, 30, 32, 32, 36, 36, 36, 36, 38, 38, 42, 42, 42, 42, 44, 44, 48, 48, 48, 48, 50, 50, 54, 54, 54, 54, 386, 386, 396, 400, 426, 426, 426, 515, 515, 515, 515, 515, 515, 515, 515, 515, 515, 515, 528

Offset

8,1

Comments

It remains to be determined if the sequence is finite.

Links

Nathan Fox, Table of n, a(n) for n = 8..227

Mathematica

Table[SelectFirst[Range[15, 10^3], Total@ Map[Function[k, DigitCount[#, k, 7]], Range[8, n]] == 0 &], {n, 8, 65}] /. n_ /; MissingQ@ n -> Nothing (* Michael De Vlieger, Mar 10 2016, Version 10.2 *)

Crossrefs

Cf. A270033, A270037, A270038, A216192, A270039, A270040, A270041, A270042, A270044, A270045.

Sequence in context: A250038 A296754 A297284 * A209726 A326455 A145449

Adjacent sequences: A270040 A270041 A270042 * A270044 A270045 A270046

Keyword

nonn,base

Author

Nathan Fox, Mar 09 2016

Status

approved