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A372502
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The number of "Fermi-Dirac primes" (A050376) that divide n.
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1
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0, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 1, 3, 1, 3, 2, 2, 1, 3, 2, 2, 2, 3, 1, 3, 1, 3, 2, 2, 2, 4, 1, 2, 2, 3, 1, 3, 1, 3, 3, 2, 1, 4, 2, 3, 2, 3, 1, 3, 2, 3, 2, 2, 1, 4, 1, 2, 3, 3, 2, 3, 1, 3, 2, 3, 1, 4, 1, 2, 3, 3, 2, 3, 1, 4, 3, 2, 1, 4, 2, 2, 2
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OFFSET
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1,4
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COMMENTS
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Differs from A345222 at n = 64, 128, 192, 320, 384, ... .
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LINKS
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FORMULA
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Sum_{k=1..n} a(k) ~ n * (log(log(n)) + B + C), where B is Mertens's constant (A077761), C = Sum_{k>=1} P(2^k) = 0.53331724743088069672..., and P(s) is the prime zeta function.
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MATHEMATICA
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f[p_, e_] := BitLength[e]; a[1] = 0; a[n_] := Plus @@ f @@@ FactorInteger[n]; Array[a, 100]
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PROG
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(PARI) a(n) = vecsum(apply(x -> exponent(x) + 1, factor(n)[, 2]));
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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