|
|
A101789
|
|
Safe primes of the form 8*k-1: primes of the form 8*k-1 such that 4*k-1 is also a prime.
|
|
2
|
|
|
7, 23, 47, 167, 263, 359, 383, 479, 503, 719, 839, 863, 887, 983, 1319, 1367, 1439, 1487, 1823, 2039, 2063, 2207, 2447, 2879, 2903, 2999, 3023, 3119, 3167, 3623, 3863, 4007, 4079, 4127, 4679, 4703, 4799, 4919, 5087, 5399, 5639, 5807, 5879, 5927, 6047
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
4*1-1 = 3 and 8*1-1 = 7 are primes, so the first term is 7.
|
|
MATHEMATICA
|
Select[Prime[Range[800]], Mod[#, 8]==7&&PrimeQ[(#-1)/2]&] (* Harvey P. Dale, Jan 31 2012 *)
|
|
PROG
|
(PARI) is(k) = (k % 8 == 7) && isprime(k) && isprime(k\2); \\ Amiram Eldar, May 23 2024
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004
|
|
STATUS
|
approved
|
|
|
|