

A131544


Least power of 3 having exactly n consecutive 9's in its decimal representation.


2



2, 34, 35, 276, 1520, 2342, 8882, 32313, 164065, 265693, 1123487, 2421341, 6250773, 9995032
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OFFSET

1,1


COMMENTS

No more terms < 2*10^7.


LINKS

Table of n, a(n) for n=1..14.


EXAMPLE

a(3)=35 because 3^35 (i.e., 50031545098999707) is the smallest power of 3 to contain a run of 3 consecutive nines in its decimal form.


MATHEMATICA

a = ""; Do[ a = StringJoin[a, "9"]; b = StringJoin[a, "9"]; k = 1; While[ StringPosition[ ToString[3^k], a] == {}  StringPosition[ ToString[3^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]


PROG

(Python)
def A131544(n):
....m, s = 1, '9'*n
....for i in range(1, 10**9):
........m *= 3
........if s in str(m):
............return i
....return "search limit reached." # Chai Wah Wu, Dec 11 2014


CROSSREFS

Sequence in context: A180342 A232591 A098869 * A123284 A123606 A062864
Adjacent sequences: A131541 A131542 A131543 * A131545 A131546 A131547


KEYWORD

more,nonn,base


AUTHOR

Shyam Sunder Gupta, Aug 26 2007


EXTENSIONS

a(11)a(14) from Lars Blomberg, Feb 02 2013


STATUS

approved



