A105563 - OEIS

%I #11 Feb 16 2025 08:32:57

%S 0,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,

%T 0,1,0,0,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,

%U 1,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0

%N a(n) = if (exactly 4 Fibonacci numbers exist with exactly n digits) then 1, otherwise 0.

%C The sequence is almost periodic, see also A105564;

%C a(n) = 1 - A105565(n) for n > 1.

%D Juergen Spilker, Die Ziffern der Fibonacci-Zahlen, Elemente der Mathematik 58 (Birkhäuser, 2003).

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FibonacciNumber.html">Fibonacci Number</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AlmostPeriodicFunction.html">Almost Periodic Function</a>

%t If[#==4,1,0]&/@Tally[IntegerLength/@Fibonacci[Range[500]]][[;;,2]] (* _Harvey P. Dale_, Nov 15 2023 *)

%Y Cf. A050815, A060384, A000045.

%K nonn,base,changed

%O 1,1

%A _Reinhard Zumkeller_, Apr 14 2005