This site is supported by donations to The OEIS Foundation.

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

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

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