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A051248 n^a(n) is smallest power of n (with a(n) > 1) which starts with n. 8
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

Reinhard Zumkeller and Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 275 terms from Reinhard Zumkeller)

EXAMPLE

2^8 = 256 begins with 2, 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

Cf. A045537, A104782.

Sequence in context: A154349 A268068 A073601 * A228615 A267823 A063664

Adjacent sequences:  A051245 A051246 A051247 * A051249 A051250 A051251

KEYWORD

nonn,base,nice

AUTHOR

Michel ten Voorde

EXTENSIONS

More terms from Jud McCranie

STATUS

approved

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Last modified July 20 01:16 EDT 2019. Contains 325168 sequences. (Running on oeis4.)