id:A120630 - OEIS Search Results

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A120630

Dirichlet inverse of A002654.

+0
1

1, -1, 0, 0, -2, 0, 0, 0, -1, 2, 0, 0, -2, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, -2, 0, 0, 0, 0, 2, 0, 0, -2, 0, 0, 0, -2, 0, 0, 0, 2, 0, 0, 0, -1, -1, 0, 0, -2, 0, 0, 0, 0, 2, 0, 0, -2, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, -2, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 4, 0, 0, 0, -2, -2, 0, 0, 0, 0, 0, 0, -2, 1, 0, 0, -2, 0, 0, 0, 0, 2, 0, 0, -2, 0, 0, 0, -2, 0, 0, 0, 2, 0, 0 (list; graph; listen)

	OFFSET	`1,5`
	FORMULA	`Multiplicative function with a(p^e)=0 if e>2. a(2)=-1, a(4)=0. If p is a prime congruent to 3 modulo 4, then a(p)=0 and a(p^2)=-1. If p is a prime congruent to 1 modulo 4, then a(p)=-2 and a(p^2)=1.`
	EXAMPLE	`a(65)=4 because 65 is 5 times 13 and both of those primes are congruent to 1 modulo 4. Doubling an odd index yields the opposite of the value (e.g., a(130)=-4) because a(2)=-1. Doubling an even index yields zero.`
	CROSSREFS	`Cf. A002654, A023900, A046692, A053822, A053825, A053826, A101035.` `Adjacent sequences: A120627 A120628 A120629 this_sequence A120631 A120632 A120633` `Sequence in context: A132406 A079126 A025891 this_sequence A089605 A060016 A117408`
	KEYWORD	`mult,easy,sign`
	AUTHOR	`Gerard P. Michon (g.michon(AT)att.net), Jun 25 2006`

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Last modified July 4 09:27 EDT 2009. Contains 160562 sequences.

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