id:A055631 - OEIS Search Results

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Sum of EulerPhi of distinct primes dividing n.

+0
3

0, 1, 2, 1, 4, 3, 6, 1, 2, 5, 10, 3, 12, 7, 6, 1, 16, 3, 18, 5, 8, 11, 22, 3, 4, 13, 2, 7, 28, 7, 30, 1, 12, 17, 10, 3, 36, 19, 14, 5, 40, 9, 42, 11, 6, 23, 46, 3, 6, 5, 18, 13, 52, 3, 14, 7, 20, 29, 58, 7, 60, 31, 8, 1, 16, 13, 66, 17, 24, 11, 70, 3, 72, 37, 6, 19, 16, 15, 78, 5, 2 (list; graph; listen)

	OFFSET	`1,3`
	FORMULA	`a(n)=Sum[p; p divides n]=A006093(n)-A001221(n)` `Additive with a(p^e) = p-1: a(10) = a(25) = a(2)+a(5) = (2-1)+(5-1) = 5; a(28) = a(2^27) = a(2^2)+a(7) = 1+6 = 7. - Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 23 2001`
	EXAMPLE	`If n=p^w, a power of prime than a(n)=p-1; if n=2p, then a(n)=p=n/2.`
	CROSSREFS	`Cf. A001221, A006093, A053570, A053571, A055632.` `Sequence in context: A055176 A118267 A075348 this_sequence A004560 A076981 A147965` `Adjacent sequences: A055628 A055629 A055630 this_sequence A055632 A055633 A055634`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu) Jun 06 2000`

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Last modified December 5 23:38 EST 2009. Contains 170428 sequences.

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