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A215727 a(n) is the smallest m for which 3^m contains n consecutive identical digits. 17
0, 11, 32, 33, 274, 538, 2124, 7720, 22791, 107187, 107187, 639226, 5756979, 8885853, 68353787, 78927180, 78927180 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

3^(a(16)+1) contains exactly 16 consecutive 3's. - Bert Dobbelaere, Mar 20 2019

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

3^11 = 177147, which has two digits in a row.

MATHEMATICA

A215727[n_] := Module[{m = 0 , t}, t = Table[i, {i, 0, 9}, {n}];

While[True, If[ContainsAny[Subsequences[IntegerDigits[3^m], {n}], t], Return[m], m++]]; m]; Table[A215727[n], {n, 1, 14}] (* Robert Price, Oct 16 2018 *)

PROG

(Python)

def A215727(n):

    l, x = [str(d)*n for d in range(10)], 1

    for m in range(10**9):

        s = str(x)

        for k in l:

            if k in s:

                return m

        x *= 3

    return 'search limit reached'

# Chai Wah Wu, Dec 17 2014

CROSSREFS

Cf. A215733, A045875.

Sequence in context: A060857 A045982 A059134 * A007790 A195857 A048773

Adjacent sequences:  A215724 A215725 A215726 * A215728 A215729 A215730

KEYWORD

nonn,base,more

AUTHOR

V. Raman, Aug 22 2012

EXTENSIONS

a(12) from Chai Wah Wu, Dec 17 2014

a(13)-a(14) from Giovanni Resta, Apr 20 2016

a(15) from Bert Dobbelaere, Mar 04 2019

a(16)-a(17) from Bert Dobbelaere, Mar 20 2019

STATUS

approved

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Last modified June 2 17:02 EDT 2020. Contains 334787 sequences. (Running on oeis4.)