login
A063784
Primes that are the sum of cubes of divisors of some integer.
3
73, 757, 1772893, 48551233240513, 378890487846991, 3156404483062657, 17390284913300671, 280343912759041771, 319913861581383373, 487014306953858713, 7824668707707203971, 8443914727229480773, 32564717507686012813, 48095468363380957093, 54811417636756749151
OFFSET
1,1
COMMENTS
Primes of the form p^6 + p^3 + 1 where p is a prime. - Amiram Eldar, Aug 16 2024
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harry J. Smith)
FORMULA
Primes of form p = sigma_3(k).
From Amiram Eldar, Aug 16 2024: (Start)
a(n) = A001158(A063783(n)).
a(n) = A060883(A066100(n)). (End)
EXAMPLE
sigma_3(9) = 1 + 27 + 729 = 757, a prime.
MATHEMATICA
Select[Table[p^6 + p^3 + 1, {p, Prime[Range[500]]}], PrimeQ] (* Amiram Eldar, Aug 16 2024 *)
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Aug 17 2001
STATUS
approved