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Search: id:A102746
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| A102746 |
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Number of distinct prime factors of concatenation of first n primes. |
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+0
1
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| 1, 1, 2, 1, 3, 3, 2, 3, 3, 3, 5, 4, 3, 4, 3, 4, 4, 4, 2, 2, 3, 4, 3, 4, 4, 5, 2, 5, 3, 6, 5, 5, 7, 7, 7, 4, 4, 6, 4, 9
(list; graph; listen)
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OFFSET
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1,3
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LINKS
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Dario Alejandro Alpern, Factorization using the Elliptic Curve Method.
Hisanori Mishima, Smarandache consecutive prime sequences (n = 1 to 100).
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EXAMPLE
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The number of distinct prime factors of 2 is 1 since it is a prime.
The number of distinct prime factors of 23 is 1 since it is a prime.
The number of distinct prime factors of 235 is 2.
The number of distinct prime factors of 2357 is 1 since it is a prime.
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MATHEMATICA
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f[n_] := Length[ FactorInteger[ FromDigits[ Flatten[ Table[ IntegerDigits[ Prime[i]], {i, n}]] ]]]; Table[ f[n], {n, 15}] (from Robert G. Wilson v Feb 22 2005)
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CROSSREFS
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Sequence in context: A046819 A159945 A089216 this_sequence A123143 A128133 A032434
Adjacent sequences: A102743 A102744 A102745 this_sequence A102747 A102748 A102749
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KEYWORD
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nonn,base
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Feb 08 2005
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 22 2005
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