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!)
A097415 Values of k such that the first digit of 2^k is 9. 1
53, 63, 73, 83, 93, 156, 166, 176, 186, 249, 259, 269, 279, 289, 352, 362, 372, 382, 445, 455, 465, 475, 485, 548, 558, 568, 578, 641, 651, 661, 671, 734, 744, 754, 764, 774, 837, 847, 857, 867, 930, 940, 950, 960, 970, 1033, 1043, 1053, 1063, 1126 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The asymptotic density of this sequence is 1 - log_10(9) = 0.045757... (A104140). - Amiram Eldar, Jan 27 2021

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Gelfand's Question.

MATHEMATICA

Select[Range[1200], IntegerDigits[2^#][[1]]==9&] (* Harvey P. Dale, Nov 30 2019 *)

CROSSREFS

Cf. A000079, A104140.

Sequence in context: A102635 A036268 A326169 * A061946 A039531 A115936

Adjacent sequences:  A097412 A097413 A097414 * A097416 A097417 A097418

KEYWORD

nonn,base

AUTHOR

Eric W. Weisstein, Aug 16 2004

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 16 16:43 EDT 2022. Contains 353707 sequences. (Running on oeis4.)