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A215728 a(n) is the smallest m for which 5^m contains n consecutive identical digits. 14
0, 11, 50, 95, 125, 1087, 2786, 2790, 2796, 2797, 2802, 2803, 1040703, 5547565, 7761841, 17876345 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(13) > 893000. - Chai Wah Wu, Dec 17 2014

LINKS

Table of n, a(n) for n=1..16.

PROG

(Python)

def A215728(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 *= 5

    return 'search limit reached'

# Chai Wah Wu, Dec 17 2014

CROSSREFS

Cf. A215734, A045875.

Sequence in context: A241964 A306425 A241406 * A185019 A212560 A211920

Adjacent sequences:  A215725 A215726 A215727 * A215729 A215730 A215731

KEYWORD

nonn,base,more

AUTHOR

V. Raman, Aug 22 2012

EXTENSIONS

a(13)-a(14) from Giovanni Resta, Apr 19 2016

a(15)-a(16) from Bert Dobbelaere, Feb 13 2019

STATUS

approved

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Last modified July 13 11:39 EDT 2020. Contains 335687 sequences. (Running on oeis4.)