|
|
A321582
|
|
Primes p such that (4*p+1)/5 is prime.
|
|
2
|
|
|
241, 421, 541, 571, 751, 1171, 1291, 1621, 1861, 2011, 2221, 2251, 2341, 2521, 2671, 2851, 2971, 3271, 3361, 3391, 3541, 3571, 3691, 4021, 4201, 4591, 4621, 4861, 5641, 5701, 5821, 6211, 6961, 7321, 7351, 7591, 7951, 8101, 8161, 8191, 8221, 8821, 8971, 9151, 9241, 9421
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
241 is a term since it is prime and (4*241+1)/5 = 193, prime.
|
|
MAPLE
|
for n from 4 to 1000 do
Y := ithprime(n);
Z := 4*Y+1;
K := (1/5)*Z;
if mod(Z, 5) = 0 and isprime(K) then print(Y);
end if:
end do:
|
|
MATHEMATICA
|
Select[Prime[Range[1000]], PrimeQ[(4 # + 1)/5] &] (* Amiram Eldar, Nov 13 2018 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|