login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A179658 Minimal odd k such that k*2^n-1 and k*2^(n+1)-1 are Sophie Germain primes. 0
3, 1, 3, 15, 45, 3, 99, 45, 51, 141, 153, 177, 411, 45, 45, 267, 237, 75, 75 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..19.

K. Bonath, First SG

EXAMPLE

Example for n=7: a(7)=99 because 99*2^7-1 and 99*2^8-1 is the first occurance for n=7 as a Sophie Germain prime pair.

CROSSREFS

Cf. A076806 (minimal odd k such that k*2^n-1 and k*2^n+1 are twin primes).

Sequence in context: A216021 A173424 A143081 * A112811 A197272 A276639

Adjacent sequences:  A179655 A179656 A179657 * A179659 A179660 A179661

KEYWORD

nonn

AUTHOR

Karsten Bonath, Jul 23 2010

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 March 24 19:48 EDT 2019. Contains 321448 sequences. (Running on oeis4.)