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A093817 Largest prime factor of 2^n-3. 2

%I #22 Sep 12 2022 05:59:22

%S 1,5,13,29,61,5,23,509,1021,409,4093,431,16381,6553,71,2473,23831,97,

%T 1048573,2713,4194301,1677721,16777213,70051,5197,31033,1877171,

%U 536870909,46684427,22605091,464773,296204641,3360037,6871947673,283007

%N Largest prime factor of 2^n-3.

%H Amiram Eldar, <a href="/A093817/b093817.txt">Table of n, a(n) for n = 2..626</a> (terms 2..200 from Vincenzo Librandi)

%F a(n) = A006530(A036563(n)). - _Amiram Eldar_, Sep 12 2022

%t PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; Table[ PrimeFactors[2^n - 3][[ -1]], {n, 2, 46}] (* _Robert G. Wilson v_, May 24 2004 *)

%t Table[FactorInteger[2^n-3][[-1,1]],{n,2,40}] (* _Harvey P. Dale_, Feb 01 2015 *)

%Y Cf. A006530, A036563, A050414, A050415, A093810.

%K nonn

%O 2,2

%A _Yasutoshi Kohmoto_, May 11 2004

%E More terms from _Robert G. Wilson v_, May 24 2004

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Last modified April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)