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A328956
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Numbers k such that sigma_0(k) = omega(k) * Omega(k), where sigma_0 = A000005, omega = A001221, Omega = A001222.
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12
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6, 10, 12, 14, 15, 18, 20, 21, 22, 24, 26, 28, 33, 34, 35, 38, 39, 40, 44, 45, 46, 48, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 65, 68, 69, 74, 75, 76, 77, 80, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 104, 106, 111, 112, 115, 116, 117
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OFFSET
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1,1
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COMMENTS
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First differs from A084227 in having 60.
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LINKS
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FORMULA
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EXAMPLE
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The sequence of terms together with their prime indices begins:
6: {1,2}
10: {1,3}
12: {1,1,2}
14: {1,4}
15: {2,3}
18: {1,2,2}
20: {1,1,3}
21: {2,4}
22: {1,5}
24: {1,1,1,2}
26: {1,6}
28: {1,1,4}
33: {2,5}
34: {1,7}
35: {3,4}
38: {1,8}
39: {2,6}
40: {1,1,1,3}
44: {1,1,5}
45: {2,2,3}
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MATHEMATICA
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Select[Range[100], DivisorSigma[0, #]==PrimeOmega[#]*PrimeNu[#]&]
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CROSSREFS
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(Omega(n) - 1) * omega(n) is A307409(n).
sigma_0(n) - omega(n) * Omega(n) is A328958(n).
sigma_0(n) - 2 - (Omega(n) - 1) * omega(n) is A328959(n).
Cf. A000040, A005117, A060687, A070175, A090858, A112798, A303555, A320632, A328960, A328961, A328962, A328963, A328964, A328965.
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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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