A250445 a(n) = gcd(n!, Fibonacci(n)) as n runs through A250444.

2, 3, 5, 2, 5, 13, 2, 37, 2, 13, 2, 3, 5, 5, 2, 73, 13, 5, 2, 3, 2, 5, 13, 89, 2, 3, 2, 2, 89, 5, 5, 157, 2, 13, 3, 2, 2, 89, 3, 193, 2, 13, 5, 3, 2, 5, 13, 2, 5, 3, 3, 2, 89, 5, 2, 3, 277, 13, 3, 5, 233, 13, 2, 5, 2, 313, 89, 2, 2, 13, 3, 2, 89, 5, 5, 13, 233, 2, 2, 397, 233, 3, 2, 3, 5

Offset

1,1

Comments

By the definition of A250444, all terms are prime.

Links

Table of n, a(n) for n=1..85.

Example

For n = 9, GCD(9!, Fibonacci(9)) = 2, (prime, thus belongs to the sequence).

Mathematica

a[n_] := GCD[n!, Fibonacci[n]];
p[n_] := Which[PrimeQ[a[n]], a[n], PrimeQ[a[n]] == False, ];
Select[Table[p[n], {n, 1, 300}], IntegerQ[#] &]

Prog

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

Crossrefs

Cf. A000045, A000142, A250444.

Sequence in context: A370590 A125766 A093870 * A297996 A239692 A126833

Adjacent sequences: A250442 A250443 A250444 * A250446 A250447 A250448

Keyword

nonn,easy

Author

Carlos Eduardo Olivieri, Nov 23 2014

Extensions

More terms from Derek Orr, Nov 23 2014

Status

approved