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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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified January 20 14:40 EST 2019. Contains 319333 sequences. (Running on oeis4.)