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 A105504 #5 Oct 07 2016 12:06:59 %S A105504 19,24,43,48,62,67,72,86,91,110,115,129,134,153,158,177,182,196,201, %T A105504 220,225,244,249,263,268,287,292,311,316,330,335,354,359,373,378,383, %U A105504 397,402,421,426,440,445,450,464,469,488,493,507,512,517,531,536,555,560 %N A105504 Numbers m such that 4 is the leading digit of the n-th Fibonacci number in decimal representation. %C A105504 A008963(a(n)) = 4; A105514(a(n)) = A105514(a(n) - 1) + 1. %F A105504 a(n) ~ kn by the equidistribution theorem, where k = log(10)/(log(5) - log(4)) = 10.318851.... - _Charles R Greathouse IV_, Oct 07 2016 %e A105504 a(10)=110: A008963(110) = A000030(A000045(110)) = %e A105504 A000030(43566776258854844738105) = 4. %o A105504 (PARI) is(n)=digits(fibonacci(n))[1]==4 \\ _Charles R Greathouse IV_, Oct 07 2016 %Y A105504 Cf. A000030, A000045, A072702, A105501, A105502, A105503, A105505, A105506, A105507, A105508, A105509. %K A105504 nonn,base %O A105504 1,1 %A A105504 _Reinhard Zumkeller_, Apr 11 2005