id:A129076 - OEIS Search Results

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a(n) = sigma(sigma(sigma(sigma(n)))), where sigma(n) = sum of divisors of n.

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1, 8, 15, 24, 56, 120, 60, 168, 60, 120, 120, 360, 168, 480, 480, 104, 120, 360, 252, 728, 210, 248, 480, 1512, 104, 728, 546, 1170, 336, 992, 210, 576, 504, 1170, 504, 480, 480, 1512, 1170, 1344, 728, 1680, 504, 1560, 1512, 992, 504, 1560, 384, 432, 992, 588 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(n) = A000203(A000203(A000203(A000203(n)))).`
	PROGRAM	`(MAGMA) [ SumOfDivisors(SumOfDivisors(SumOfDivisors(SumOfDivisors(n)))) : n in [1..100]];`
	CROSSREFS	`Cf. A000203, A051027, A066971.` `Adjacent sequences: A129073 A129074 A129075 this_sequence A129077 A129078 A129079` `Sequence in context: A034104 A034114 A069826 this_sequence A072177 A031125 A132298`
	KEYWORD	`easy,nonn`
	AUTHOR	`Jonathan Vos Post (jvospost2(AT)yahoo.com), May 27 2007`

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.

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