id:A078439 - OEIS Search Results

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Sum_{k=1..n} gcd(k,n)*mu(gcd(k,n))^2.

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1, 3, 5, 4, 9, 15, 13, 8, 12, 27, 21, 20, 25, 39, 45, 16, 33, 36, 37, 36, 65, 63, 45, 40, 40, 75, 36, 52, 57, 135, 61, 32, 105, 99, 117, 48, 73, 111, 125, 72, 81, 195, 85, 84, 108, 135, 93, 80, 84, 120, 165, 100, 105, 108, 189, 104, 185, 171, 117, 180, 121, 183, 156, 64 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(n) = Sum_{d\|n} dmu(d)^2phi(n/d). Multiplicative with a(p) = 2p-1 and a(p^e) = 2(p-1)*p^(e-1), e>1.`
	CROSSREFS	`Cf. A008683, A000010, A063659.` `Sequence in context: A082568 A069918 A075380 this_sequence A007063 A127397 A167808` `Adjacent sequences: A078436 A078437 A078438 this_sequence A078440 A078441 A078442`
	KEYWORD	`mult,nonn`
	AUTHOR	`Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 31 2002`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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