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A072983
Denominator of b(n)=sum (k'<=n,1/k') where k' denotes the squarefree numbers.
2
1, 2, 6, 6, 30, 5, 35, 35, 35, 70, 770, 770, 10010, 5005, 15015, 15015, 255255, 255255, 4849845, 4849845, 1616615, 3233230, 74364290, 74364290, 74364290, 37182145, 37182145, 37182145, 1078282205, 6469693230, 200560490130, 200560490130
OFFSET
1,2
COMMENTS
b(n) was used by Niven in the 1970's for an alternative proof of the divergence of the sum of reciprocals of the primes.
LINKS
Ivan Niven, A Proof of the Divergence of sum 1/p, The American Mathematical Monthly, Vol. 78, No. 3 (Mar., 1971), pp. 272-273.
PROG
(PARI) a(n)=denominator(sum(k=1, n, issquarefree(k)/k))
CROSSREFS
Cf. A072980.
Sequence in context: A087310 A130087 A085087 * A055204 A212397 A008339
KEYWORD
easy,frac,nonn
AUTHOR
_Benoit Cloitre_, Aug 21 2002
STATUS
approved