A277213 Least k such that Fibonacci(k + 1) has n times as many distinct prime factors as Fibonacci(k), or 0 if no such k exists.
3, 7, 17, 23, 29, 47, 167, 419, 83
Offset: 1
Examples
a(2) = 7 because Fibonacci(8) = 21 = 3*7 (2 distinct prime factors) and Fibonacci(7) = 13 (1 prime factor), and 2/1 is 2.
Programs
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Mathematica
Flatten[Table[Position[Partition[PrimeNu[Fibonacci[Range[2,420]]],2,1],?(k #[[1]]==#[[2]]&),1,1,Heads->False],{k,9}]]+1 (* _Harvey P. Dale, Jan 31 2025 *)
Extensions
a(8)-a(9) from Charles R Greathouse IV, Oct 05 2016
Comments