|
|
A240838
|
|
Primes p such that prime(p) + 2*p^2 is prime.
|
|
0
|
|
|
2, 3, 5, 13, 41, 43, 139, 173, 227, 239, 359, 463, 541, 691, 743, 761, 821, 823, 827, 887, 1021, 1117, 1289, 1427, 1489, 1637, 1723, 1933, 1999, 2081, 2287, 2309, 2719, 2791, 2833, 2843, 2953, 3329, 3541, 3803, 3823, 3929, 4003, 4007, 4079, 4139, 4297, 4451, 4561, 4597, 4691, 4703, 4817, 4931, 4943
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
The associated primes are: 11, 23, 41, 379, 3541, ...
|
|
LINKS
|
|
|
EXAMPLE
|
2 is in this sequence because 2 and prime(2) + 2*2^2 = 3 + 8 = 11 are both prime.
|
|
MATHEMATICA
|
Select[Prime[Range[700]], PrimeQ[Prime[#]+2#^2]&] (* Harvey P. Dale, Mar 19 2018 *)
|
|
PROG
|
(Magma) [n: n in {1..5000} | IsPrime(n) and IsPrime(s) where s is (2*n^2 + NthPrime(n))];
(PARI) isok(p) = isprime(p) && isprime(prime(p) + 2*p^2); \\ Michel Marcus, Apr 13 2014
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|