id:A090780 - OEIS Search Results

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a(n)= n*prod_{ p prime, p|n} (p-1)/2.

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1, 1, 3, 2, 10, 3, 21, 4, 9, 10, 55, 6, 78, 21, 30, 8, 136, 9, 171, 20, 63, 55, 253, 12, 50, 78, 27, 42, 406, 30, 465, 16, 165, 136, 210, 18, 666, 171, 234, 40, 820, 63, 903, 110, 90, 253, 1081, 24, 147, 50, 408, 156, 1378, 27, 550, 84, 513, 406, 1711, 60, 1830, 465, 189 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(2n+1) is the conjectured value of the length of period of sequence of Genocchi number of first kind read modulo (2n+1) (cf. A001469)`
	FORMULA	`a(n)=(n/(-2)^omega(n))(sum_{d\|n} dmu(d))`
	CROSSREFS	`Sequence in context: A092502 A135515 A114486 this_sequence A063549 A057977 A071653` `Adjacent sequences: A090777 A090778 A090779 this_sequence A090781 A090782 A090783`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 12 2004`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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