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Search: id:A155457
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| A155457 |
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a(n) = exp(Lambda(n)), where Lambda(n) is the von Mangoldt function for odd (!) primes. |
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1
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| 1, 1, 3, 1, 5, 1, 7, 1, 3, 1, 11, 1, 13, 1, 1, 1, 17, 1, 19, 1, 1, 1, 23, 1, 5, 1, 3, 1, 29, 1, 31, 1, 1, 1, 1, 1, 37, 1, 1, 1, 41, 1, 43, 1, 1, 1, 47, 1, 7, 1, 1, 1, 53, 1, 1, 1, 1, 1, 59, 1, 61, 1, 1, 1, 1, 1, 67, 1, 1, 1, 71, 1, 73, 1, 1, 1, 1, 1, 79, 1, 3, 1, 83, 1, 1, 1, 1, 1, 89
(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) = p if n = p^k and p odd prime, k >= 1, otherwise 1.
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REFERENCES
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Tom M. Apostol, Introduction to analytic number theory, Springer-Verlag, 1976.
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LINKS
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Wikipedia, Von Mangoldt function
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EXAMPLE
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a(8) = 1 because 8 = 2^3 is not the power of an odd prime, a(49) = 7 because 49 = 7^2.
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MAPLE
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a := proc(n) local lcm; lcm := n -> ilcm(seq(i, i = 1..n)); if type(n, even) then 1 else lcm(n)/lcm(n-1) fi end;
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CROSSREFS
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Cf. A014963.
Sequence in context: A087913 A090585 A147661 this_sequence A009001 A093178 A093411
Adjacent sequences: A155454 A155455 A155456 this_sequence A155458 A155459 A155460
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KEYWORD
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nonn
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AUTHOR
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Peter Luschny (peter(AT)luschny.de), Jan 22 2009, Jan 25 2009
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