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A104484
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Number of distinct prime divisors of 33...331 (with n 3s).
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5
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1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 2, 2, 3, 1, 3, 4, 3, 2, 4, 3, 3, 2, 4, 3, 3, 2, 3, 4, 6, 2, 2, 3, 3, 4, 4, 1, 3, 3, 6, 6, 3, 2, 3, 5, 3, 1, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,8
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COMMENTS
| Interestingly, the first seven members in this sequence are all primes.
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EXAMPLE
| Number of distinct prime divisors of 31 is 1 (prime).
Number of distinct prime divisors of 331 is 1 (prime).
Number of distinct prime divisors of 3331 is 1 (prime).
Number of distinct prime divisors of 33331 is 1 (prime).
Number of distinct prime divisors of 333331 is 1 (prime).
Number of distinct prime divisors of 3333331 is 1 (prime).
Number of distinct prime divisors of 33333331 is 1 (prime).
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MATHEMATICA
| Table[Length[FactorInteger[(10^(n + 1) - 7)/3]], {n, 1, 50}] (Steinerberger)
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CROSSREFS
| Sequence in context: A139801 A132328 A064822 * A038809 A078342 A177903
Adjacent sequences: A104481 A104482 A104483 * A104485 A104486 A104487
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KEYWORD
| nonn
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AUTHOR
| Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Apr 18 2005
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