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A105971
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Number of distinct prime divisors of 66...667 (with n 6's).
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1
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1, 1, 2, 2, 2, 1, 2, 1, 1, 3, 1, 3, 3, 4, 3, 3, 3, 2, 4, 1, 2, 2, 1, 2, 5, 2, 4, 4, 3, 4, 3, 3, 3, 3, 4, 3, 4, 3, 4, 2, 1, 3, 5, 4, 4, 6, 6, 5, 4, 2, 4, 4, 4, 6, 5, 4, 4, 3, 3, 5, 5, 3, 1, 4, 5, 1, 5, 5, 5, 4, 3, 2, 4, 4, 4, 4, 5, 4, 5, 6, 2, 7, 6, 4, 7, 5, 5, 4, 5, 2, 5, 4, 3, 6, 4, 6, 6, 4, 3, 5
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OFFSET
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0,3
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LINKS
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FORMULA
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EXAMPLE
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The number of distinct prime divisors of 67 is 1 (prime).
The number of distinct prime divisors of 667 is 2.
The number of distinct prime divisors of 6667 is 2.
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MATHEMATICA
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Table[PrimeNu[(6*10^(n + 1) + 3)/9], {n, 0, 30}] (* Amiram Eldar, Jan 27 2020 *)
Table[PrimeNu[FromDigits[PadLeft[{7}, n, 6]]], {n, 100}] (* Harvey P. Dale, Apr 05 2023 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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