A060901 Exact power of 3 that divides the n-th Fibonacci number (sequence A000045).

1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 27, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 27, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1

Offset: 1

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), May 05 2001

Keywords

• nonn
• easy

Examples

			a(12) = 9 because the 12th Fibonacci number is 144 and 144 = 9*16.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000045, A060865.

Cf. A038500.

Programs

Haskell

a060901 = a038500 . a000045  -- Reinhard Zumkeller, Feb 04 2015

PARI

a(n) = 3^valuation(fibonacci(n), 3) \\Michel Marcus, Jul 30 2013

Formula

If n is not divisible by 4 then a(n) = 1, if n = 4 * 3^k * m where m is not divisible by 3 then a(n) = 3^(k+1).

a(n) = A038500(A000045(n)). - Michel Marcus, Jul 30 2013

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001