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

 

Logo

110 people attended OEIS-50 (videos, suggestions); annual fundraising drive to start soon (donate); editors, please edit! (stack is over 300), your editing is more valuable than any donation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A183076 Composite numbers of the form 2^k - 1 for which each prime divisor has the form 4j + 3. 7
63, 1023, 16383, 32767, 67108863, 1073741823, 17179869183, 274877906943, 8796093022207, 2251799813685247, 4611686018427387903, 36893488147419103231 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Needed factorizations are in the Cunningham Project.

LINKS

Table of n, a(n) for n=1..12.

S. S. Wagstaff, Jr., The Cunningham Project.

FORMULA

a(n) = 2^A183072(n) - 1

EXAMPLE

63 = 2^6 - 1 = 3^2 * 7, and 3 and 7 have the form 4j + 3.

CROSSREFS

Cf. A000668, A136005, A183075, A183077, A183078

Cf. A000043, A136003, A183071, A183072, A183073, A183074

Sequence in context: A232794 A091027 A112494 * A230660 A132465 A202983

Adjacent sequences:  A183073 A183074 A183075 * A183077 A183078 A183079

KEYWORD

nonn,hard

AUTHOR

Stuart Clary, Dec 23, 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified October 30 14:20 EDT 2014. Contains 248813 sequences.