OFFSET
1,1
EXAMPLE
n=100, prime(100) = 541, start at 541!, the list is: {541!,...,46374,195,21,10,7} so a(100)=7.
MATHEMATICA
sopfr[n_] := Total[Times @@@ FactorInteger[n]]; a[n_] := FixedPoint[sopfr, Prime[n]!]; Array[a, 100] (* Jean-François Alcover, May 06 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 08 2003
STATUS
approved