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A136031 Largest prime factor of composite Mersenne numbers. 7
89, 178481, 2089, 616318177, 164511353, 2099863, 13264529, 20394401, 3203431780337, 761838257287, 212885833, 9361973132609, 1113491139767, 57912614113275649087721, 13842607235828485645766393, 341117531003194129, 3976656429941438590393 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..183

FORMULA

a(n) >= A089158(n). - R. J. Mathar, May 01 2008

MATHEMATICA

FactorInteger[2^#-1][[-1, 1]]&/@Select[Prime[Range[40]], !PrimeQ[2^#-1]&] (* Harvey P. Dale, May 05 2012 *)

CROSSREFS

Cf. A049479, A016047, A003260, A136030.

Sequence in context: A073905 A089158 A145098 * A145097 A287054 A080051

Adjacent sequences:  A136028 A136029 A136030 * A136032 A136033 A136034

KEYWORD

nonn

AUTHOR

Artur Jasinski, Dec 11 2007

EXTENSIONS

Corrected by Harvey P. Dale, May 05 2012

STATUS

approved

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Last modified April 17 07:52 EDT 2021. Contains 343060 sequences. (Running on oeis4.)