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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
 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, 46, 47, 50, 51, 52, 53, 56, 57, 58, 59, 62, 65, 68, 69, 70, 71, 74, 75, 76, 77, 82, 83, 86, 87, 88, 89, 92, 93, 94, 95, 98, 99, 104, 107, 112, 113, 116, 117, 118, 119, 122, 123, 124 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES J.-M. De Koninck, Ces nombres qui nous fascinent, Footnote pp 18, Ellipses, Paris 2008. LINKS Amiram Eldar, Table of n, a(n) for n = 1..629 CROSSREFS Cf. A000225, A005117. Sequence in context: A276878 A047247 A169606 * A032877 A032844 A023775 Adjacent sequences:  A140766 A140767 A140768 * A140770 A140771 A140772 KEYWORD nonn AUTHOR Lekraj Beedassy, Jul 13 2008 STATUS approved

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Last modified November 25 07:54 EST 2020. Contains 338618 sequences. (Running on oeis4.)