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A171266 Primes of the form 1 + triperfect numbers. 0
673, 523777 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A subsequence of A093034.

If p is a term of this sequence then for each positive integer k, x=p^k

is a solution for the equation sigma(phi(x))=3(x-1). See comment lines of

the sequence A093034.

LINKS

Table of n, a(n) for n=1..2.

Achim Flammenkamp, The Multiply Perfect Numbers Page

EXAMPLE

p=673 is prime and sigma(p-1)/(p-1)=3, so p is in the sequence.

CROSSREFS

Cf. A005820, A093034, A171263, A171264, A171265.

Sequence in context: A297123 A160209 A234117 * A267818 A158392 A264328

Adjacent sequences:  A171263 A171264 A171265 * A171267 A171268 A171269

KEYWORD

fini,full,nonn,bref

AUTHOR

M. F. Hasler and Farideh Firoozbakht, Apr 15 2010

STATUS

approved

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)