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 A060865 #22 Aug 04 2025 13:56:29
%S A060865 1,1,2,1,1,8,1,1,2,1,1,16,1,1,2,1,1,8,1,1,2,1,1,32,1,1,2,1,1,8,1,1,2,
%T A060865 1,1,16,1,1,2,1,1,8,1,1,2,1,1,64,1,1,2,1,1,8,1,1,2,1,1,16,1,1,2,1,1,8,
%U A060865 1,1,2,1,1,32,1,1,2,1,1,8,1,1,2,1,1,16,1,1,2,1,1,8,1,1,2,1,1,128,1,1,2,1
%N A060865 a(n) is the exact power of 2 that divides the n-th Fibonacci number (A000045).
%H A060865 Robert Israel, <a href="/A060865/b060865.txt">Table of n, a(n) for n = 1..10000</a>
%F A060865 If n is not divisible by 3 then a(n) = 1, if n = 3 * 2^k * (2m + 1) then a(n) = 2 if k=0 or 2^(k+2) if k>0.
%F A060865 a(n) = F(n) / A174883(n). - _Franklin T. Adams-Watters_, Jan 24 2012
%F A060865 a(n) = A006519(A000045(n)). - _Michel Marcus_, Jul 30 2013
%F A060865 a(3n) = 2^A090740(n). - _Robert Israel_, Dec 28 2015
%e A060865 a(12) = 16 because the 12th Fibonacci number is 144 and 144 = 9*16.
%p A060865 seq(2^padic:-ordp(combinat:-fibonacci(n),2),n=1..100); # _Robert Israel_, Dec 28 2015
%t A060865 Table[2^IntegerExponent[Fibonacci[n],2],{n,100}] (* _Harvey P. Dale_, Aug 04 2025 *)
%o A060865 (PARI) a(n)=2^valuation(fibonacci(n), 2) \\_Michel Marcus_, Jul 30 2013
%Y A060865 Cf. A000045, A060904(n) = 5^A112765(n), A090740.
%K A060865 nonn,easy
%O A060865 1,3
%A A060865 Ahmed Fares (ahmedfares(AT)my-deja.com), May 04 2001
%E A060865 More terms from Larry Reeves (larryr(AT)acm.org), May 07 2001