id:A069193 - OEIS Search Results

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Sum_{d|n} d*phi(n)/phi(d).

+0
2

1, 3, 5, 10, 9, 15, 13, 28, 24, 27, 21, 50, 25, 39, 45, 72, 33, 72, 37, 90, 65, 63, 45, 140, 70, 75, 99, 130, 57, 135, 61, 176, 105, 99, 117, 240, 73, 111, 125, 252, 81, 195, 85, 210, 216, 135, 93, 360, 140, 210, 165, 250, 105, 297, 189, 364, 185, 171, 117, 450 (list; graph; listen)

	OFFSET	`1,2`
	MAPLE	`with(numtheory):for n from 1 to 200 do di := sort(convert(divisors(n), list)): a[n] := sum(di[i]*phi(n)/phi(di[i]), i=1..nops(di)):od:seq(a[k], k=1..200);`
	CROSSREFS	`Cf. A000010.` `Sequence in context: A098339 A121622 A083519 this_sequence A078430 A113858 A101130` `Adjacent sequences: A069190 A069191 A069192 this_sequence A069194 A069195 A069196`
	KEYWORD	`mult,easy,nonn`
	AUTHOR	`Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 10 2002`
	EXTENSIONS	`More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Feb 02 2003`

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Last modified November 25 14:49 EST 2009. Contains 167514 sequences.

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