id:A082540 - OEIS Search Results

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Number of ordered quadruples (a,b,c,d) with gcd(a,b,c,d)=1 (1<= {a,b,c,d} <= n.).

+0
1

1, 15, 79, 239, 607, 1199, 2303, 3823, 6223, 9279, 13919, 19183, 27007, 35743, 47519, 60735, 78719, 97103, 122447, 148527, 181839, 216959, 262543, 306863, 365343, 423855, 495855, 569055, 661679, 748527, 862047, 972191, 1104831, 1237247 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(n)=sum(k=1, n, mu(k)floor(n/k)^4); a(n) is asymptotic to cn^4 with c=0.92393....`
	PROGRAM	`(PARI) a(n)=sum(k=1, n, moebius(k)*floor(n/k)^4)`
	CROSSREFS	`Cf. A018805 (pairs), A071778 (triples).` `Sequence in context: A081591 A044202 A044583 this_sequence A085808 A033594 A059377` `Adjacent sequences: A082537 A082538 A082539 this_sequence A082541 A082542 A082543`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), May 11 2003`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

AT&T Labs Research