|
|
A247845
|
|
Primes, p, that generate the prime quadruplets, p^2-2p+2k (for k = -2, -1, 1, 2).
|
|
2
|
|
|
5, 62417, 178817, 261017, 419147, 433787, 505607, 876107, 1183337, 1374377, 1620917, 1976987, 3619607, 4146377, 5260487, 5622047, 6399677, 7166147, 7213847, 7743647, 8055167, 10615967, 13277717, 14042117, 14080277, 15331397, 17433407, 17889587, 17963867
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Except for a(1), all other terms in the sequence end in 7.
For a similar list not restricted to primes, see A247882.
|
|
LINKS
|
|
|
EXAMPLE
|
5 is in the sequence as it generates the prime quadruplet 5^2-2*5-4=11; 5^2-2*5-2=13; 5^2-2*5+2=17; and, 5^2-2*5+4=19.
|
|
PROG
|
(PARI) lista(nn) = {vk = [-2, -1, 1, 2]; forprime (p=2, nn, nb = 0; for (k=1, 4, nb += isprime(p^2-2*p+2*vk[k]); ); if (nb == 4, print1(p, ", ")); ); } \\ Michel Marcus, Sep 26 2014
(Magma) [p: p in PrimesUpTo(10^7) |IsPrime(p^2-2*p-4) and IsPrime(p^2-2*p-2)and IsPrime(p^2-2*p+2)and IsPrime(p^2-2*p+4)]; // Vincenzo Librandi, Oct 14 2014
|
|
CROSSREFS
|
Cf. A247846 (lesser of prime quadruplets), A247882 (similar but not restricted to primes).
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|