id:A049645 - OEIS Search Results

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(divisors(n))^2 divides sum of divisors of n.

+0
2

1, 3, 7, 11, 19, 21, 23, 31, 33, 35, 43, 47, 57, 59, 62, 67, 69, 71, 77, 79, 83, 91, 93, 94, 103, 105, 107, 115, 119, 127, 129, 131, 133, 139, 141, 151, 155, 158, 161, 163, 167, 177, 179, 186, 189, 191, 199, 201, 203, 209, 211, 213, 217, 223 (list; graph; listen)

	OFFSET	`1,2`
	REFERENCES	`Handbook of Number Theory, D. S. Mitrinovic et al., Kluwer, Section III.51.`
	MAPLE	`with(numtheory): t := [ ]: f := [ ]: for n from 1 to 500 do if sigma(n) mod sigma[ 0 ](n)^2 = 0 then t := [ op(t), n ] else f := [ op(f), n ]; fi; od: t;`
	CROSSREFS	`Cf. A003601, A049642, A049692.` `Sequence in context: A062851 A071979 A097748 this_sequence A167181 A049835 A117510` `Adjacent sequences: A049642 A049643 A049644 this_sequence A049646 A049647 A049648`
	KEYWORD	`nonn`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com).`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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