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
Keywords
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.
Programs
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Magma
[Maximum(PrimeDivisors(Fibonacci(NthPrime(n)))): n in [2..35]];
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Mathematica
Table[FactorInteger[Fibonacci [Prime[n]]][[-1, 1]], {n, 2, 30}]
Formula
From Amiram Eldar, Oct 25 2024: (Start)
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)