id:A086823 - OEIS Search Results

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Coefficient of x^2 in the n-th cyclotomic polynomial. (The same as the coefficient of x^(phi(n)-2) ).

+0
1

0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, -1, 1, 1, 0, 0, 1, 0, 1, -1, 0, 1, 1, 0, 0, 1, 0, -1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, -1, 0, 1, 1, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, -1, 0, 0, 1, 0, 1, 1, 0, -1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, -1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1 (list; graph; listen)

	OFFSET	`3,1`
	FORMULA	`if n is odd a(n) = 1/2 * mu(n)(mu(n)-1) if n is even a(n) = 1/2 mu(n)*(mu(n)-1) - mu(n/2).`
	PROGRAM	`(PARI) a(n) = polcoeff(polcyclo(n), 2); (Wasserman)`
	CROSSREFS	`Cf. A008683, A000010.` `Sequence in context: A095190 A131735 A131736 this_sequence A104121 A063524 A084928` `Adjacent sequences: A086820 A086821 A086822 this_sequence A086824 A086825 A086826`
	KEYWORD	`sign`
	AUTHOR	`Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 07 2003`
	EXTENSIONS	`More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Mar 29 2005`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

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