This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A138859 #16 Jun 24 2023 04:21:01
%S A138859 7,3,11,3,3,5,199,13,13,3,37,3,3,89,5,11,7,3,59,3,3,11,11,37,37,3,
%T A138859 370248451,3,3,139,13,5,5,3,5,3,3,59,709,557,127,3,11,3,3,5,9375829,
%U A138859 73,7,3,29,3,3,2789,5,11,47,3,13,3,3,11,11,13,7,3,809,3,3,953,47927441,5,5
%N A138859 Smallest prime factor of Fibonacci(3n)-1, i.e., A020639(A000071(3n)).
%C A138859 F(n)-1 is even if n is not a multiple of 3.
%H A138859 Amiram Eldar, <a href="/A138859/b138859.txt">Table of n, a(n) for n = 2..934</a> (terms 2..379 from Chai Wah Wu)
%F A138859 a(n) = A020639(A000071(3n)).
%t A138859 Table[FactorInteger[Fibonacci[3n]-1][[1,1]],{n,2,80}] (* _Harvey P. Dale_, Aug 08 2017 *)
%o A138859 (PARI) A138859(n)=factor(fibonacci(3*n)-1)[1,1] /* A138859 is defined only for n>1 ! */
%Y A138859 Cf. A000071, A014445, A020639.
%K A138859 nonn
%O A138859 2,1
%A A138859 _M. F. Hasler_, Apr 05 2008