OFFSET
1,1
COMMENTS
Also equal to primes p such that 5*p-4 is a perfect square.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[(Range[500]^2+4)/5, PrimeQ] (* Harvey P. Dale, Jul 13 2014 *)
PROG
(Python)
import sympy
L = (k**2 + 4 for k in range(10**3))
[n//5 for n in L if n % 5 == 0 and sympy.ntheory.isprime(n//5)]
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Jul 10 2014
STATUS
approved