

A131550


a(n) is the least exponent e such that 3^e has exactly n consecutive 3's in its decimal representation.


9



1, 31, 119, 185, 511, 2341, 9671, 7721, 67449, 364579, 513334, 639227, 6250772, 30377688, 82011443, 78927181
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OFFSET

1,2


COMMENTS

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


LINKS

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


EXAMPLE

a(3)=119 because 3^119 (i.e., 599003433304810403471059943169868346577158542512617035467) is the smallest power of 3 to contain a run of 3 consecutive threes in its decimal form.


MATHEMATICA

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


CROSSREFS

Cf. A195269, A131552, A131551, A131549, A131548, A131547, A131546, A131545, A131544.
Sequence in context: A254283 A010019 A256650 * A158558 A160893 A202994
Adjacent sequences: A131547 A131548 A131549 * A131551 A131552 A131553


KEYWORD

more,nonn,base


AUTHOR

Shyam Sunder Gupta, Aug 26 2007


EXTENSIONS

a(11)a(13) from Lars Blomberg, Feb 02 2013
a(14)a(16) from Bert Dobbelaere, Mar 20 2019


STATUS

approved



