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A106752
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Numbers of prime factors of k, k defined in A117078.
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1
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0, 0, 1, 0, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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COMMENTS
| a(n) = 0 only for n = 1, 2 and 4.
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LINKS
| Remi Eismann, Table of n, a(n) for n = 1..10000
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FORMULA
| a(n) = numbers of factors of A117078(n). A117078(n) : smallest k such that prime(n+1) = prime(n) + (prime(n) mod k), or 0 if no such k exists.
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EXAMPLE
| For a(1), k=0 thus a(1)=0,
For a(3), k=3 thus a(3)=1,
For a(11), k=25=5*5 thus a(11)=2.
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CROSSREFS
| Cf. A117078, A117563, A118534, A118144, A118123.
Sequence in context: A128184 A025450 A139128 * A136441 A030561 A202053
Adjacent sequences: A106749 A106750 A106751 * A106753 A106754 A106755
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KEYWORD
| nonn
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AUTHOR
| Remi Eismann (reismann(AT)free.fr), Jun 22 2007, Feb 14 2008
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