The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 20 14:08 EDT 2024. Contains 372717 sequences. (Running on oeis4.)