id:A062952 - OEIS Search Results

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Multiplicative with a(p^e) = (p^(2*e+2)-p^(e+1)-p^e+p)/(p^2-1).

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1, 4, 9, 18, 25, 36, 49, 78, 87, 100, 121, 162, 169, 196, 225, 326, 289, 348, 361, 450, 441, 484, 529, 702, 645, 676, 807, 882, 841, 900, 961, 1334, 1089, 1156, 1225, 1566, 1369, 1444, 1521, 1950, 1681, 1764, 1849, 2178, 2175, 2116, 2209, 2934, 2443, 2580 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`If y is square-free (cf. A005117(n)) then A062952(y)=y^2 - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 16 2002`
	FORMULA	`a(n) = Sum_{d\|n} phi(d)*sigma(d). a(n) = Sum_{k=1..n} sigma(n/gcd(n, k)).`
	CROSSREFS	`Cf. A057660, A029939.` `Sequence in context: A139468 A162719 A064599 this_sequence A100435 A160172 A026412` `Adjacent sequences: A062949 A062950 A062951 this_sequence A062953 A062954 A062955`
	KEYWORD	`mult,nonn`
	AUTHOR	`Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 21 2001`

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.

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