login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A305415
Numbers k such that F(k)*F(k+1) - F(k+2) is prime, where F = A000045.
0
4, 6, 7, 8, 10, 11, 14, 25, 34, 40, 44, 54, 62, 63, 66, 108, 190, 266, 299, 306, 310, 343, 350, 638, 726, 984, 1626, 2223, 2591, 2843, 3291, 3694, 4198, 4473, 4494, 5128, 7934, 10595, 12515, 17433, 17883, 19979, 23887, 28847, 30071, 64168, 79073, 81971
OFFSET
1,1
COMMENTS
Primes in A059769: 7, 83, 239, 659, 4751, 12583, 228983, 9107313407, 52623175261103, 16944503546101559, 796030992711071707, 12041560801669230246323, etc.
MAPLE
with(combinat, fibonacci): select(n->isprime(fibonacci(n)*fibonacci(n+1)-fibonacci(n+2)), [$1..8000]); # Muniru A Asiru, Jun 12 2018
MATHEMATICA
Select[Range[3000], PrimeQ[(Fibonacci[#] Fibonacci[# + 1] - Fibonacci[# + 2])]&]
PROG
(Magma) [n: n in [1..800] | IsPrime(Fibonacci(n)*Fibonacci(n+1)-Fibonacci(n+2))];
(PARI) isok(k) = isprime(fibonacci(k)*fibonacci(k+1) - fibonacci(k+2)); \\ Michel Marcus, Jun 13 2018
CROSSREFS
Sequence in context: A171413 A225551 A247359 * A105432 A324704 A203168
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Jun 09 2018
EXTENSIONS
a(38)-a(46) from Giovanni Resta, Jun 15 2018
a(47)-a(48) from Robert Price, Jun 18 2018
STATUS
approved