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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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EXAMPLE
| 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
| 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:
seq(A104660(n), n=1..45) ; # R. J. Mathar, Aug 23 2011
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MATHEMATICA
| Table[PrimeNu[FromDigits[Join[Table[4, {n}], {3}]]], {n, 50}] (* From Alonso del Arte, Aug 23 2011 *)
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CROSSREFS
| Cf. A104518, A173770
Sequence in context: A104469 A144112 A178568 * A093613 A118816 A097289
Adjacent sequences: A104657 A104658 A104659 * A104661 A104662 A104663
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KEYWORD
| nonn,base
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AUTHOR
| Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Apr 21 2005
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EXTENSIONS
| More terms from R. J. Mathar and Alonso del Arte, Aug 23 2011
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