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A072326 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). +0
1
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.

Adjacent sequences: A072323 A072324 A072325 this_sequence A072327 A072328 A072329

Sequence in context: A043760 A043769 A039525 this_sequence A068700 A135850 A019283

KEYWORD

nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Jul 31 2002

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.


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