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!)
A051248 n^a(n) is the smallest power of n (with a(n) > 1) which starts with n. 10
2, 8, 18, 6, 24, 10, 20, 11, 22, 2, 26, 14, 10, 8, 92, 6, 166, 5, 19, 11, 60, 39, 48, 51, 94, 42, 467, 86, 14, 66, 58, 3, 5268, 33, 58, 10, 45, 70, 23, 6, 205, 70, 31, 15, 50, 84, 248, 70, 72, 94, 107, 170, 30, 10139, 182, 136, 87, 318, 49, 10, 178, 237, 295, 99, 17, 206 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A070327(n) = n^a(n) for n > 1. - Reinhard Zumkeller, Sep 29 2011
The largest of the first 10000 terms is a(1955) = 119589011. - Giovanni Resta, May 27 2016
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 275 terms from Reinhard Zumkeller)
EXAMPLE
2^8 = 256 begins with 2, and 2^k does not begin with 2 for any smaller integer k > 1, so a(2) = 8.
MATHEMATICA
f[n_]:=Module[{i=2}, While[Take[IntegerDigits[n^i], IntegerLength[n]] != IntegerDigits[n], i++]; i]; Array[f, 70] (* Harvey P. Dale, Oct 04 2011 *)
PROG
(Haskell)
import Data.List (isPrefixOf)
a051248 n = 2 + length
(takeWhile (not . (show n `isPrefixOf`) . show) $ iterate (* n) (n^2))
-- Reinhard Zumkeller, Sep 29 2011
CROSSREFS
Sequence in context: A154349 A268068 A073601 * A228615 A267823 A063664
KEYWORD
nonn,base,nice
AUTHOR
EXTENSIONS
More terms from Jud McCranie
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 June 12 16:34 EDT 2024. Contains 373334 sequences. (Running on oeis4.)