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A200334 Decimal expansion of Sum_{n = 2 .. infinity }[ 1 / Sum {i=1..m} d(i)^n] where d(i) are the distinct prime divisors of n and m = omega(n) is the number of distinct prime divisors of n. 0
3, 5, 5, 0, 9, 3, 5, 7, 1, 9, 3, 0, 6, 7, 7, 6, 2, 3, 6, 2, 7, 3, 7, 6, 9, 0, 2, 2, 4, 3, 3, 8, 8, 8, 8, 8, 5, 8, 9, 0, 6, 1, 7, 3, 5, 8, 7, 9, 6, 8, 1, 0, 5, 2, 5, 4, 1, 3, 1, 3, 9, 9, 4, 4, 8, 7, 4, 3, 6, 9, 9, 3, 7, 8, 7, 8, 2, 3, 1, 3, 9, 7, 9, 8, 3, 5, 1, 2, 5, 1, 9, 1, 3, 1, 5, 8, 0, 7, 9, 3, 7, 1, 5, 8, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..104.

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

Sequence in context: A021742 A284867 A152416 * A138112 A106233 A198492

Adjacent sequences:  A200331 A200332 A200333 * A200335 A200336 A200337

KEYWORD

nonn,cons

AUTHOR

Michel Lagneau, Nov 28 2011

STATUS

approved

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Last modified October 21 20:44 EDT 2019. Contains 328315 sequences. (Running on oeis4.)