login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

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

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.

License Agreements, Terms of Use, Privacy Policy. .

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