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A063784 Primes that are the sum of cubes of divisors of an integer. 2
73, 757, 1772893, 48551233240513, 378890487846991, 3156404483062657, 17390284913300671, 280343912759041771, 319913861581383373, 487014306953858713, 7824668707707203971, 8443914727229480773 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

Primes of form p = sigma(3, x).

EXAMPLE

sigma(3,9) = 1 + 27 + 729 = 757, a prime.

PROG

(PARI) { n=0; p=0; for (m=1, 10^9, p=nextprime(p+1); if(isprime(q=p^6 + p^3 + 1), write("b063784.txt", n++, " ", q); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 31 2009

CROSSREFS

Cf. A001158, A023194.

Sequence in context: A112750 A177514 A137835 * A066101 A272768 A100412

Adjacent sequences:  A063781 A063782 A063783 * A063785 A063786 A063787

KEYWORD

nonn

AUTHOR

Labos Elemer, Aug 17 2001

STATUS

approved

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Last modified October 21 03:24 EDT 2019. Contains 328291 sequences. (Running on oeis4.)