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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A145097 a(n) = largest divisor of the Mersenne composite A065341(n) 3
89, 178481, 2304167, 616318177, 164511353, 20408568497, 59862819377, 1416003655831, 3203431780337, 761838257287, 10334355636337793, 21514198099633918969, 224958284260258499201, 57912614113275649087721 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Note that not all the largest divisors are primes.

Which divisors are prime? - see A145099. [From Artur Jasinski, Oct 04 2008]

LINKS

Table of n, a(n) for n=1..14.

MATHEMATICA

a = {}; Do[m = 2^Prime[n] - 1; If[PrimeQ[m], null, AppendTo[a, Divisors[m][[ -2]]]], {n, 1, 40}]; a (*Artur Jasinski*)

CROSSREFS

A065341, A135975, A135980, A145098

Sequence in context: A089158 A145098 A136031 * A080051 A243316 A072314

Adjacent sequences:  A145094 A145095 A145096 * A145098 A145099 A145100

KEYWORD

nonn

AUTHOR

Artur Jasinski, Oct 01 2008

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 December 20 23:02 EST 2014. Contains 252290 sequences.