|
|
A245048
|
|
Primes p such that p^2 + 28 is prime.
|
|
1
|
|
|
3, 5, 11, 13, 17, 19, 23, 41, 43, 47, 53, 67, 79, 83, 89, 97, 109, 131, 137, 149, 157, 163, 167, 179, 181, 193, 211, 223, 239, 241, 251, 263, 277, 281, 311, 317, 331, 379, 397, 401, 409, 421, 431, 439, 443, 449, 457, 467, 479, 541, 569, 599, 643, 647, 673
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
7 of the first 8 odd primes are in this list.
|
|
LINKS
|
|
|
EXAMPLE
|
3 is in the sequence because 3^2 + 28 = 37, which is also prime.
5 is in the sequence because 5^2 + 28 = 53, which is also prime.
7 is not in the sequence because 7^2 + 28 = 77 = 7 * 11.
|
|
MAPLE
|
|
|
MATHEMATICA
|
Select[Prime[Range[200]], PrimeQ[#^2 + 28] &] (* Alonso del Arte, Jul 12 2014 *)
|
|
PROG
|
(Python)
import sympy
[sympy.prime(n) for n in range(1, 10**6) if sympy.ntheory.isprime(sympy.prime(n)**2+28)]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|