

A084599


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


3



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

1,1


COMMENTS

Like the EuclidMullin sequence A000946, but subtracting rather than adding 1 to the product.


LINKS

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


EXAMPLE

a(4)=29 since 2*3*5=30 and 29 is the largest prime factor of 301
a(5)=79 since 2*3*5*29=870 and 79 is the largest prime factor of 8701=869=11*79.


CROSSREFS

Cf. A000946, A005265, A084598.
Essentially the same as A005266.
Sequence in context: A215103 A038962 A019400 * A062167 A279189 A107451
Adjacent sequences: A084596 A084597 A084598 * A084600 A084601 A084602


KEYWORD

nonn


AUTHOR

Marc LeBrun, May 31 2003


EXTENSIONS

More terms from Hugo Pfoertner, May 31, 2003, using Dario Alpern's ECM.
The next term a(15) is not known. It requires the factorization of the 245digit composite number which remains after eliminating 7 smaller factors.


STATUS

approved



