id:A072326 - OEIS Search Results

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Conjectured values of n such that the sum of proper divisors of x*n is never prime for any x>=1 (i.e. sigma(xn)-xn is never prime for x>=1).

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42, 78, 84, 114, 126, 156, 168, 174, 186, 210 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`It seems that a(n) == 0 (mod 6)`
	CROSSREFS	`Cf. A001065, A037020.` `Sequence in context: A043760 A043769 A039525 this_sequence A068700 A135850 A153644` `Adjacent sequences: A072323 A072324 A072325 this_sequence A072327 A072328 A072329`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Jul 31 2002`

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