A020911 Number of digits in the base 3 representation of n-th Fibonacci number.

1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 9, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 16, 17, 17, 18, 18, 19, 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 23, 24, 24, 25, 25, 26, 26, 26, 27, 27, 28, 28, 29, 29, 30, 30, 30

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Crossrefs

Cf. A000045 (Fibonacci numbers), A081604 (base-3 digits of n).

Programs

Magma

[#Intseq(Fibonacci(n),3):n in [1..70]]; // Marius A. Burtea, Jan 02 2020

Mathematica

IntegerLength[Fibonacci[Range[50]],3] (* Harvey P. Dale, Aug 13 2018 *)

PARI

a(n)={1 + logint(fibonacci(n), 3)} \\ Andrew Howroyd, Jan 01 2020

Formula

a(n) = A081604(A000045(n)). - Andrew Howroyd, Jan 01 2020

Extensions

Offset corrected and terms a(50) and beyond from Andrew Howroyd, Jan 01 2020