A217188 a(n) is the number of digits in the decimal representation of the smallest power of 6 that contains n consecutive identical digits.

1, 4, 4, 90, 176, 289, 1170, 6640, 21569, 21569, 54421

Offset

1,2

Comments

Number of digits in 6^k is equal to floor(1 + k*log_10(6)).

Links

Table of n, a(n) for n=1..11.

Mathematica

k = 0; Join[{1}, Table[While[d = IntegerDigits[6^k]; prt = Partition[Differences[d], n - 1, 1]; ! MemberQ[prt, Table[0, {n - 1}]], k++]; Length[d], {n, 2, 8}]] (* T. D. Noe, Oct 03 2012 *)

Crossrefs

Cf. A215729, A215735.

Sequence in context: A131592 A317868 A224092 * A092209 A068337 A009534

Adjacent sequences: A217185 A217186 A217187 * A217189 A217190 A217191

Keyword

nonn,base

Author

V. Raman, Sep 27 2012

Extensions

a(11) added by V. Raman, Nov 23 2013

Status

approved