OFFSET
1,1
LINKS
Robert Israel and Amiram Eldar, Table of n, a(n) for n = 1..60 (terms 1..57 from Robert Israel)
Florian Luca and Igor E. Shparlinski, On the largest prime factor of n! + 2^n - 1, Journal de Theorie des Nombres de Bordeaux 17 (2005), 859-870.
FORMULA
MAPLE
seq(max(numtheory:-factorset(n!+2*n-1)), n=1..30); # Robert Israel, Jun 28 2018
MATHEMATICA
a = {}; Do[k = n! + 2 n - 1; c = First[Last[FactorInteger[k]]]; AppendTo[a, c], {n, 1, 40}]; a (*Artur Jasinski*)
Table[FactorInteger[n!+2n-1][[-1, 1]], {n, 30}] (* Harvey P. Dale, Aug 31 2011 *)
PROG
(PARI) a(n)=my(f=factor(n!+2*n-1)[, 1]); f[#f] \\ Charles R Greathouse IV, Feb 01 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 22 2008
EXTENSIONS
More terms from Robert Israel, Jun 28 2018
STATUS
approved