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A100857
a(n) = greatest prime factor of (prime(n) - 1)! + prime(n).
3
3, 5, 29, 727, 3628811, 6599, 6385271, 1291883, 315389197, 123662437024088191, 2107707330310062524424576119, 50717732086848522419, 14602944428087660261, 55353784249983832172137, 16166897314580017
OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..24 (using factordb.com)
FactorDB, Status of 97+96!.
FORMULA
a(n) = A006530(A100856(n)).
a(n) > A000040(n).
EXAMPLE
n=6: (prime(6)-1)! + prime(6) = 12! + 13 = 479001600 + 13 = 479001613 = 29*2503*6599, therefore a(6) = 6599.
MATHEMATICA
FactorInteger[(#-1)!+#][[-1, 1]]&/@Prime[Range[15]] (* Harvey P. Dale, Jul 23 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Nov 20 2004
STATUS
approved