OFFSET
1,2
COMMENTS
n=0 would give the prime 2 but positive n is required. Some terms correspond to probable primes. a(15) > 40000. - Jens Kruse Andersen, Aug 04 2014
MAPLE
with(combinat): A245801:=n->`if`(isprime(fibonacci(3*n+1)+fibonacci(3*n-1)-fibonacci(n)), n, NULL): seq(A245801(n), n=1..1000); # Wesley Ivan Hurt, Aug 04 2014
MATHEMATICA
Select[Range[3000], PrimeQ[LucasL[3 #] - Fibonacci[#]] &]
PROG
(Magma) [n: n in [1..800] | IsPrime(Lucas(3*n) - Fibonacci(n))];
(Python)
import sympy
{print(n, end=', ') for n in range(10**3) if sympy.isprime(sympy.lucas(3*n)-sympy.fibonacci(n))} # Derek Orr, Aug 03 2014
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
Vincenzo Librandi, Aug 02 2014
EXTENSIONS
21491 from Jens Kruse Andersen, Aug 04 2014
STATUS
approved