A325627 a(n) is the largest prime factor in A030426(n).

2, 5, 13, 89, 233, 1597, 113, 28657, 514229, 2417, 2221, 59369, 433494437, 2971215073, 55945741, 2710260697, 555003497, 1429913, 46165371073, 86020717, 92180471494753, 99194853094755497, 1665088321800481, 361040209, 770857978613, 512119709, 8242065050061761

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..222

C. L. Stewart, On Divisors of Fermat, Fibonacci, Lucas, and Lehmer Numbers, Proceedings of the London Mathematical Society, Vol. s3-35, No. 3 (1977), pp. 425-447. See p. 430.

Formula

From Amiram Eldar, Oct 25 2024: (Start)

a(n) = A006530(A030426(n)).

a(n) = A060385(prime(n+1)).

a(n) > c * prime(n) * log(prime(n)), where c is an effectively computable positive constant (Stewart, 1977). (End)

Mathematica

Table[FactorInteger[Fibonacci [Prime[n]]][[-1, 1]], {n, 2, 30}]

Prog

(Magma) [Maximum(PrimeDivisors(Fibonacci(NthPrime(n)))): n in [2..35]];

Crossrefs

Cf. A000045, A005478, A006530, A030426, A060385, A325626.

Sequence in context: A236395 A032015 A325626 * A075736 A030426 A075742

Adjacent sequences: A325624 A325625 A325626 * A325628 A325629 A325630

Keyword

nonn

Author

Vincenzo Librandi, May 13 2019

Status

approved