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Revision History for A084599

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a(1) = 2, a(2) = 3; for n >= 2, a(n+1) is largest prime factor of (Product_{k=1..n} a(k)) - 1.
(history; published version)

#9 by Alois P. Heinz at Sat Jul 08 14:14:20 EDT 2023

STATUS

proposed

approved

#8 by Dario Alpern at Sat Jul 08 14:09:49 EDT 2023

STATUS

editing

proposed

#7 by Dario Alpern at Sat Jul 08 14:09:40 EDT 2023

LINKS

Dario Alpern, <a href="httphttps://www.alpertron.com.ar/ECM.HTM">ECMFactorization using the Elliptic Curve Method</a>

STATUS

approved

editing

Discussion

Sat Jul 08

14:09

Dario Alpern: Fixed link

#6 by Russ Cox at Sat Mar 31 10:29:02 EDT 2012

EXTENSIONS

More terms from _Hugo Pfoertner (hugo(AT)pfoertner.org), _, May 31, 2003, using Dario Alpern's ECM.

Discussion

Sat Mar 31

10:29

OEIS Server: https://oeis.org/edit/global/581

#5 by Russ Cox at Fri Mar 30 17:38:11 EDT 2012

AUTHOR

_Marc LeBrun (mlb(AT)well.com), _, May 31 2003

Discussion

Fri Mar 30

17:38

OEIS Server: https://oeis.org/edit/global/183

#4 by N. J. A. Sloane at Sun Jun 29 03:00:00 EDT 2008

CROSSREFS

Cf. A000946, A005265, A084598.

Essentially the same as A005266.

KEYWORD

nonn,new

nonn

#3 by N. J. A. Sloane at Sat Jun 12 03:00:00 EDT 2004

NAME

a(1) = 2, a(2) = 3, ; for n >= 2, a(n+1) is largest prime factor of (Product_{k=1..n} a(k) ) - 1.

EXAMPLE

a(5)=79 since 2*3*5*29=870 and 79 is the largest prime factor of 870-1=869=11*79.

KEYWORD

nonn,new

nonn

#2 by N. J. A. Sloane at Thu Feb 19 03:00:00 EST 2004

KEYWORD

nonn,new

nonn

EXTENSIONS

More terms from Hugo Pfoertner (allhugo(AT)abouthugopfoertner.deorg), May 31, 2003, using Dario Alpern's ECM.

#1 by N. J. A. Sloane at Sat Sep 13 03:00:00 EDT 2003

NAME

a(1) = 2, a(2) = 3, a(n+1) is largest prime factor of Product_{k=1..n} a(k) - 1.

DATA

2, 3, 5, 29, 79, 68729, 3739, 6221191, 157170297801581, 70724343608203457341903, 46316297682014731387158877659877, 78592684042614093322289223662773, 181891012640244955605725966274974474087, 547275580337664165337990140111772164867508038795347198579326533639132704344301831464707648235639448747816483406685904347568344407941

OFFSET

1,1

COMMENTS

Like the Euclid-Mullin sequence A000946, but subtracting rather than adding 1 to the product.

LINKS

Dario Alpern, <a href="http://www.alpertron.com.ar/ECM.HTM">ECM</a>

EXAMPLE

a(4)=29 since 2*3*5=30 and 29 is the largest prime factor of 30-1

CROSSREFS

Cf. A000946, A084598.

KEYWORD

nonn

AUTHOR

Marc LeBrun (mlb(AT)well.com), May 31 2003

EXTENSIONS

More terms from Hugo Pfoertner (all(AT)abouthugo.de), May 31, 2003, using Dario Alpern's ECM.

The next term a(15) is not known. It requires the factorization of the 245-digit composite number which remains after eliminating 7 smaller factors.

STATUS

approved