

A131545


Least k such that 3^k has exactly n consecutive 8's in its decimal representation.


9



4, 23, 32, 215, 1261, 538, 4797, 17612, 32311, 375482, 512959, 1847532, 8295710, 8885853, 80798025
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OFFSET

1,1


COMMENTS

No more terms < 10^8.  Bert Dobbelaere, Mar 20 2019


LINKS

Table of n, a(n) for n=1..15.


EXAMPLE

a(3)=32 because 3^32 (i.e., 1853020188851841) is the smallest power of 3 to contain a run of 3 consecutive eights in its decimal form.


MATHEMATICA

a = ""; Do[ a = StringJoin[a, "8"]; b = StringJoin[a, "8"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {}  StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]


CROSSREFS

Cf. A195269, A131552, A131551, A131550, A131549, A131548, A131547, A131546, A131544.
Sequence in context: A258203 A293698 A160613 * A030716 A169599 A106684
Adjacent sequences: A131542 A131543 A131544 * A131546 A131547 A131548


KEYWORD

more,nonn,base


AUTHOR

Shyam Sunder Gupta, Aug 26 2007


EXTENSIONS

a(11)a(14) from Lars Blomberg, Feb 02 2013
a(15) from Bert Dobbelaere, Mar 20 2019


STATUS

approved



