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1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 2, 1, 1, 3, 1, 3, 2, 2, 1, 4, 1, 2, 1, 3, 1, 5, 1, 1, 2, 2, 2, 5, 1, 2, 2, 4, 1, 5, 1, 3, 3, 2, 1, 5, 1, 3, 2, 3, 1, 4, 2, 4, 2, 2, 1, 8, 1, 2, 3, 1, 2, 5, 1, 3, 2, 5, 1, 7, 1, 2, 3, 3, 2, 5, 1, 5, 1, 2, 1, 8, 2, 2, 2, 4, 1, 8, 2, 3, 2, 2, 2, 6, 1, 3, 3, 5, 1, 5, 1, 4, 5
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OFFSET
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1,6
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COMMENTS
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Number of divisors of n that are not positive powers of primes (cf. A000961). - Benoit Cloitre, May 03 2003; corrected Dec 16 2008 at the suggestion of Ray Chandler.
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LINKS
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EXAMPLE
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After first statement in comment section, a(60) = 8 because we have: 1,6,10,12,15,20,30,60. The divisors 2,3,4,5 are excluded from the count. - Geoffrey Critzer, Nov 22 2015
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MAPLE
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seq(numtheory:-tau(n)-numtheory:-bigomega(n), n=1..300); # Robert Israel, Nov 23 2015
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MATHEMATICA
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Table[DivisorSigma[0, n] - PrimeOmega[n], {n, 1, 105}] (* Geoffrey Critzer, Nov 22 2015 *)
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PROG
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(PARI) first(m)=vector(m, n, numdiv(n) - bigomega(n)) \\ Anders Hellström, Nov 22 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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