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A140769 Numbers n such that consecutive Mersenne numbers A000225(n-1) = M(n-1) = 2^(n-1) - 1 and A000225(n) = M(n) = 2^n - 1 are both squarefree. 1

%I

%S 2,3,4,5,8,9,10,11,14,15,16,17,23,26,27,28,29,32,33,34,35,38,39,44,45,

%T 46,47,50,51,52,53,56,57,58,59,62,65,68,69,70,71,74,75,76,77,82,83,86,

%U 87,88,89,92,93,94,95,98,99,104,107,112,113,116,117,118,119,122,123,124

%N Numbers n such that consecutive Mersenne numbers A000225(n-1) = M(n-1) = 2^(n-1) - 1 and A000225(n) = M(n) = 2^n - 1 are both squarefree.

%D J.-M. De Koninck, Ces nombres qui nous fascinent, Footnote pp 18, Ellipses, Paris 2008.

%H Amiram Eldar, <a href="/A140769/b140769.txt">Table of n, a(n) for n = 1..629</a>

%Y Cf. A000225, A005117.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Jul 13 2008

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Last modified December 1 20:47 EST 2021. Contains 349435 sequences. (Running on oeis4.)