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%I #21 Sep 12 2022 08:39:23
%S 1,5,13,29,61,5,11,509,1021,5,4093,19,16381,5,13,53,11,5,1048573,773,
%T 4194301,5,16777213,479,37,5,11,536870909,23,5,9241,29,5113,5,242819,
%U 47189,11,5,13,23,47,5,5927,2087,227,5,11,19,59,5,13,2203,36217,5,181
%N Smallest prime factor of 2^n-3.
%H Amiram Eldar, <a href="/A093810/b093810.txt">Table of n, a(n) for n = 2..626</a> (terms 2..200 from Vincenzo Librandi)
%F a(n) = A020639(A036563(n)). - _Amiram Eldar_, Sep 12 2022
%t PrimeFactors[n_] := Flatten[ Table[ # [[1]], {1}] & /@ FactorInteger[n]]; Table[ PrimeFactors[2^n - 3][[1]], {n, 2, 60}] (* _Robert G. Wilson v_, May 24 2004 *)
%t FactorInteger[#][[1,1]]&/@(2^Range[2,60]-3) (* _Harvey P. Dale_, Aug 21 2016 *)
%Y Cf. A020639, A036563, A050414, A050415, A093817.
%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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