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A093810 Smallest prime factor of 2^n-3. 2
1, 5, 13, 29, 61, 5, 11, 509, 1021, 5, 4093, 19, 16381, 5, 13, 53, 11, 5, 1048573, 773, 4194301, 5, 16777213, 479, 37, 5, 11, 536870909, 23, 5, 9241, 29, 5113, 5, 242819, 47189, 11, 5, 13, 23, 47, 5, 5927, 2087, 227, 5, 11, 19, 59, 5, 13, 2203, 36217, 5, 181 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 2..200

MATHEMATICA

PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; Table[ PrimeFactors[2^n - 3][[1]], {n, 2, 60}] (* Robert G. Wilson v, May 24 2004 *)

FactorInteger[#][[1, 1]]&/@(2^Range[2, 60]-3) (* Harvey P. Dale, Aug 21 2016 *)

CROSSREFS

Cf. A093817, A050414, A050415.

Sequence in context: A023617 A023619 A020576 * A093817 A120274 A036982

Adjacent sequences:  A093807 A093808 A093809 * A093811 A093812 A093813

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto, May 11 2004

EXTENSIONS

More terms from Robert G. Wilson v, May 24 2004

Typo in Mathematica code corrected by Vincenzo Librandi, May 14 2013

STATUS

approved

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Last modified April 20 03:02 EDT 2019. Contains 322293 sequences. (Running on oeis4.)