id:A072079 - OEIS Search Results

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A072079

Sum of 3-smooth divisors of n.

+0
2

1, 3, 4, 7, 1, 12, 1, 15, 13, 3, 1, 28, 1, 3, 4, 31, 1, 39, 1, 7, 4, 3, 1, 60, 1, 3, 40, 7, 1, 12, 1, 63, 4, 3, 1, 91, 1, 3, 4, 15, 1, 12, 1, 7, 13, 3, 1, 124, 1, 3, 4, 7, 1, 120, 1, 15, 4, 3, 1, 28, 1, 3, 13, 127, 1, 12, 1, 7, 4, 3, 1, 195, 1, 3, 4, 7, 1, 12, 1, 31, 121 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n) = A000203(A065331(n)).` `Multiplicative with a(2^e) = 2^(e+1)-1, a(3^e) = (3^(e+1)-1)/2, a(p^e) = 1, p>3. Christian G. Bower (bowerc(AT)usa.net) May 20, 2005.`
	FORMULA	`a(n) = (2^(A007814(n)+1)-1)*(3^(A007949(n)+1)-1)/2.`
	CROSSREFS	`Cf. A000203, A003586, A072078.` `Sequence in context: A024476 A093087 A130893 this_sequence A116073 A166043 A021292` `Adjacent sequences: A072076 A072077 A072078 this_sequence A072080 A072081 A072082`
	KEYWORD	`nonn,mult`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 13 2002`

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.

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