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 A060384 #42 Jul 12 2025 22:52:53
%S A060384 1,1,1,1,1,1,1,2,2,2,2,2,3,3,3,3,3,4,4,4,4,5,5,5,5,5,6,6,6,6,6,7,7,7,
%T A060384 7,7,8,8,8,8,9,9,9,9,9,10,10,10,10,10,11,11,11,11,11,12,12,12,12,12,
%U A060384 13,13,13,13,14,14,14,14,14,15,15,15,15,15,16,16,16,16,16,17,17,17,17,17,18
%N A060384 Number of decimal digits in n-th Fibonacci number.
%H A060384 Harry J. Smith, <a href="/A060384/b060384.txt">Table of n, a(n) for n = 0..10000</a>
%F A060384 a(n) = floor(n*log(tau)/log(10)) +0 or +1 where tau is the golden ratio. - _Benoit Cloitre_, Oct 29 2002. [Corrected by _Hans J. H. Tuenter_, Jul 07 2025].
%F A060384 a(n) = floor(n*log_10(gold) - log_10(5)/2) + 1 for n >= 2, where gold is (1+sqrt(5))/2. - Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2007
%F A060384 a(n) = A055642(A000045(n)). - _Reinhard Zumkeller_, Mar 09 2013
%p A060384 with(combinat): a:=n->nops(convert(fibonacci(n),base,10)): 1,seq(a(n),n=1..100); # _Emeric Deutsch_, May 19 2007
%t A060384 Table[IntegerLength@ Fibonacci@ n, {n, 0, 84}] /. 0 -> 1 (* or *)
%t A060384 Table[Floor[n Log10@ GoldenRatio - Log10@ 5/2] + 1, {n, 0, 84}] /. 0 -> 1 (* _Michael De Vlieger_, Jul 04 2016 *)
%o A060384 (PARI) print1("1, 1, "); gold=(1+sqrt(5))/2; for(n=2,100,print1(floor((n*log(gold)-log(5)/2)/log(10))+1", ")) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2007
%o A060384 (PARI) a(n) = #Str(fibonacci(n)); \\ _Michel Marcus_, Jul 04 2016
%o A060384 (Haskell)
%o A060384 a060384 = a055642 . a000045 -- _Reinhard Zumkeller_, Mar 09 2013
%Y A060384 Cf. A000045, A022307, A001605, A060319, A060320, A051694, A050815.
%Y A060384 Cf. A261585.
%K A060384 base,nonn
%O A060384 0,8
%A A060384 _Labos Elemer_, Apr 03 2001
%E A060384 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2007