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A072980 Numerator of b(n)=sum (k'<=n,1/k') where k' denotes the squarefree numbers. 2

%I #10 Nov 28 2013 17:34:05

%S 1,3,11,11,61,11,82,82,82,171,1951,1951,26133,13424,41273,41273,

%T 716656,716656,13871719,13871719,4700888,9548741,222854273,222854273,

%U 222854273,112857219,112857219,112857219,3310041496,20075905417

%N Numerator of b(n)=sum (k'<=n,1/k') where k' denotes the squarefree numbers.

%C b(n) was used by Niven in the 70's for an alternative proof of the divergence of the sum of reciprocal of primes.

%H Ivan Niven, <a href="http://www.jstor.org/stable/2317524">A Proof of the Divergence of sum 1/p</a>, The American Mathematical Monthly, Vol. 78, No. 3 (Mar., 1971), pp. 272-273.

%o (PARI) a(n) = numerator(sum(k=1, n, issquarefree(k)/k)); \\ _Michel Marcus_, Nov 28 2013

%Y Cf. A072983.

%K easy,frac,nonn

%O 1,2

%A _Benoit Cloitre_, Aug 21 2002

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Last modified March 4 23:31 EST 2024. Contains 370537 sequences. (Running on oeis4.)