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Search: id:A101207
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| A101207 |
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For each prime power n, a(n) is the number of positive integers that have n as their greatest prime power. |
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+0
1
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| 1, 1, 2, 2, 6, 0, 12, 8, 16, 0, 48, 0, 96, 0, 0, 48, 240, 0, 480, 0, 0, 0, 960, 0, 960, 0, 960, 0, 3840, 0, 7680, 3072, 0, 0, 0, 0, 18432, 0, 0, 0, 36864, 0, 73728, 0, 0, 0, 147456, 0, 147456, 0, 0, 0, 442368, 0, 0, 0, 0, 0, 884736, 0, 1769472, 0, 0, 589824
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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a(n) is the number of occurrences of n in A034699
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FORMULA
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a(1) = 1; a(p^k) = prod_{q <= p^k, q prime} { ceiling(k ln p / ln q) } / k when p prime, k >= 1, a(n) = 0 otherwise
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EXAMPLE
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a(4) = 2 since only 4 and 12 have 4 as their greatest prime power - all other multiples of 4 are divisible by 8, 9, or some prime >= 5.
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CROSSREFS
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Cf. A034699.
Sequence in context: A011144 A127649 A047916 this_sequence A010245 A016529 A077894
Adjacent sequences: A101204 A101205 A101206 this_sequence A101208 A101209 A101210
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KEYWORD
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nonn,easy
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AUTHOR
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hv(AT)crypt.org (Hugo van der Sanden), Dec 13 2004
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