A215729 a(n) is the smallest m for which 6^m contains (at least) n consecutive identical digits.

0, 5, 5, 115, 226, 371, 1503, 8533, 27717, 27717, 69936, 848255, 1308931, 8255246, 32564822, 39063403

Offset: 1

Author

V. Raman, Aug 22 2012

Keywords

• nonn
• base
• more
• hard

Comments

a(12) > 838000. - Chai Wah Wu, Dec 17 2014

a(14) > 7*10^6. - Giovanni Resta, Apr 20 2016

Crossrefs

Cf. A215735, A045875.

Programs

Python

def A215729(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 *= 6
    return 'search limit reached'
# Chai Wah Wu, Dec 17 2014

Extensions

a(11) from Rick van der Hoorn, Mar 26 2013

a(12)-a(13) from Giovanni Resta, Apr 19 2016

a(14) from Bert Dobbelaere, Feb 15 2019

a(15) from Paul Geneau de Lamarlière, May 26 2024

a(16) from Paul Geneau de Lamarlière, Jul 12 2024