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A104660
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Number of distinct prime divisors of 44...443 (with n 4s).
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2
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1, 1, 2, 2, 1, 3, 3, 1, 2, 2, 1, 2, 2, 3, 3, 3, 3, 3, 4, 3, 3, 6, 3, 4, 3, 3, 6, 4, 1, 5, 1, 4, 3, 5, 3, 6, 4, 2, 6, 2, 2, 3, 5, 3, 4, 4, 4, 2, 2, 4, 4, 3, 4, 5, 6, 3, 3, 5, 2, 4, 3, 5, 4, 4, 3, 6, 4, 3, 6, 6, 4, 5, 4, 2, 4, 5, 2, 4, 5, 6, 4, 4, 3, 6, 5, 4, 5
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OFFSET
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1,3
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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 43 is 1 (prime).
The number of distinct prime divisors of 443 is 1 (prime).
The number of distinct prime divisors of 4443 is 2.
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MAPLE
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A104660 := proc(n) x := [3, seq(4, k=1..n)] ; add(op(i, x)*10^(i-1), i=1..nops(x)) ; numtheory[factorset](%) ; nops(%) ; end proc:
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MATHEMATICA
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Table[PrimeNu[FromDigits[Join[Table[4, {n}], {3}]]], {n, 50}] (* Alonso del Arte, Aug 23 2011 *)
Table[PrimeNu[FromDigits[PadLeft[{3}, n, 4]]], {n, 2, 70}] (* Harvey P. Dale, Aug 22 2016 *)
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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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EXTENSIONS
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STATUS
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approved
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