id:A018806 - OEIS Search Results

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Sum of gcd(x, y) for 1 <= x, y <= n.

+0
4

1, 5, 12, 24, 37, 61, 80, 112, 145, 189, 220, 288, 325, 389, 464, 544, 593, 701, 756, 880, 989, 1093, 1160, 1336, 1441, 1565, 1700, 1880, 1965, 2205, 2296, 2488, 2665, 2829, 3028, 3328, 3437, 3621, 3832, 4152, 4273, 4621, 4748, 5040, 5373, 5597, 5736, 6168 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`Sum_{k=1..n} phi(k)*(floor(n/k))^2. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Nov 10 2002`
	CROSSREFS	`Cf. A000010, A018805, A064951.` `Sequence in context: A066869 A023172 A100479 this_sequence A126880 A108314 A079425` `Adjacent sequences: A018803 A018804 A018805 this_sequence A018807 A018808 A018809`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net)`

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

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