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A250444
Numbers n such that gcd(n!, Fibonacci(n)) is prime.
2
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
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
KEYWORD
nonn,easy
AUTHOR
STATUS
approved