OFFSET
0,1
EXAMPLE
0.3550935719306776236273769022433888885890...
MAPLE
with(numtheory):Digits:=200:s:=0:for n from 2 to 2000 do:x:=factorset(n):p:=sum(‘x[i]^n’, ’i’=1..nops(x)): s:=s+evalf(1/p):od:print(s):
MATHEMATICA
digits = 105; s[m_] := s[m] = Sum[f = FactorInteger[n][[All, 1]]; 1/Sum[p^n, {p, f}], {n, 2, m}] // RealDigits[#, 10, digits]& // First; s[digits] ; s[m = 2*digits]; While[s[m] != s[m/2], m = 2*m]; s[m] (* Jean-François Alcover, Feb 24 2014 *)
PROG
(PARI) sum(n=2, 1e3, f=factor(n)[, 1]; 1./sum(i=1, #f, f[i]^n)) \\ Charles R Greathouse IV, Nov 28 2011
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Michel Lagneau, Nov 28 2011
STATUS
approved