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A328959
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a(n) = sigma_0(n) - 2 - (omega(n) - 1) * nu(n), where sigma_0 = A000005, nu = A001221, omega = A001222.
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11
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-1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0
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OFFSET
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1,72
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COMMENTS
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Conjecture: All terms are nonnegative except for a(1) = -1.
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LINKS
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FORMULA
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EXAMPLE
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a(72) = sigma_0(72) - 2 - (omega(72) - 1) * nu(72) = 12 - 2 - (5 - 1) * 2 = 2.
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MATHEMATICA
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Table[DivisorSigma[0, n]-2-(PrimeOmega[n]-1)*PrimeNu[n], {n, 100}]
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PROG
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(PARI)
A307408(n) = 2+((bigomega(n)-1)*omega(n));
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CROSSREFS
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The positions of positive terms are conjectured to be A320632.
Positions of first appearances are A328963.
sigma_0(n) - omega(n) * nu(n) is A328958(n).
Cf. A000005, A001221, A001222, A112798, A124010, A307408, A323023, A328956, A328960, A328961, A328962, A328965.
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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