A250444 Numbers n such that gcd(n!, Fibonacci(n)) is prime.

3, 4, 5, 9, 10, 14, 33, 38, 39, 49, 51, 52, 55, 65, 69, 74, 77, 85, 87, 92, 93, 115, 119, 121, 123, 124, 129, 141, 143, 145, 155, 158, 159, 161, 172, 177, 183, 187, 188, 194, 201, 203, 205, 212, 213, 215, 217, 219, 235, 236, 244, 249, 253, 265, 267, 268, 278, 287, 292, 295, 299

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

For n = 3: GCD(3!, Fibonacci(3)) = 2.
For n = 4: GCD(4!, Fibonacci(4)) = 3.
For n = 9: GCD(9!, Fibonacci(9)) = 2.

Maple

select(n -> isprime(igcd(n!, combinat:-fibonacci(n))), [$1..1000]); # Robert Israel, Nov 24 2014

Mathematica

Select[Range[300], PrimeQ[GCD[#!, Fibonacci[#]] ] &]

Prog

(PARI) for(n=1, 10^3, if(isprime(gcd(n!, fibonacci(n))), print1(n, ", "))) \\ Derek Orr, Nov 23 2014

Crossrefs

Sequence in context: A236211 A279616 A050068 * A327178 A190211 A136120

Adjacent sequences: A250441 A250442 A250443 * A250445 A250446 A250447

Keyword

nonn,easy

Author

Carlos Eduardo Olivieri, Nov 23 2014

Status

approved