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A131544 Least power of 3 having exactly n consecutive 9's in its decimal representation. 10
2, 34, 35, 276, 1520, 2342, 8882, 32313, 164065, 265693, 1123487, 2421341, 6250773, 9995032, 68353789, 78927182 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
No more terms < 10^8. - Bert Dobbelaere, Mar 20 2019
LINKS
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: A343905 A232591 A098869 * A123284 A123606 A062864
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 04 2019
a(16) from Bert Dobbelaere, Mar 20 2019
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)