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A079579
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Totally multiplicative with p -> (p-1)*p, p prime.
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2
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1, 2, 6, 4, 20, 12, 42, 8, 36, 40, 110, 24, 156, 84, 120, 16, 272, 72, 342, 80, 252, 220, 506, 48, 400, 312, 216, 168, 812, 240, 930, 32, 660, 544, 840, 144, 1332, 684, 936, 160, 1640, 504, 1806, 440, 720, 1012, 2162, 96, 1764, 800, 1632, 624, 2756, 432, 2200, 336
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(n)<=n^2; a(n)=n iff n=2^k; a(n)=n*A003958(n).
Multiplicative sequence with a(p^e) = p^e*(p-1)^e for prime p. [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Nov 01 2009]
The Dirichlet inverse is 1, -2, -6, 0, -20, 12, -42, 0, 0, 40, -110, 0, -156, 84, 120, 0, -272, ..., i.e., the sequence defined by mu(n)*a(n). - R. J. Mathar, Dec 20 2011
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
| Dirichlet g.f.: sum_{n>=1} a(n)/n^s = product_{primes p} 1/(1+p^(1-s)-p^(2-s)). - R. J. Mathar, Dec 20 2011
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PROG
| (Haskell)
a079579 1 = 1
a079579 n = product $ zipWith (*) pfs $ map (subtract 1) pfs
where pfs = a027746_row n
-- Reinhard Zumkeller, Jan 05 2012
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CROSSREFS
| Cf. A027746.
Sequence in context: A124838 A088659 A052100 * A112326 A075435 A069875
Adjacent sequences: A079576 A079577 A079578 * A079580 A079581 A079582
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KEYWORD
| nonn,mult
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 24 2003
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