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 A030621 #12 Jul 22 2014 03:26:13 %S A030621 0,0,0,-1,-1,-1,-1,-1,-1,-1,-2,-1,-1,-1,-1,-1,-1,-2,-1,-1,-1,-1,-1,-1, %T A030621 -2,-2,-1,-1,-2,-2,-1,-2,-1,0,0,0,0,0,0,0,0,0,0,-1,-2,-1,0,0,0,0,0,-1, %U A030621 -2,-2,-2,-3,-3,-3,-3,-3,-2,-2,-2,-2,-2,-2,-3 %N A030621 (# 4's)-(# 5's) in first n terms of A030604. %H A030621 Vincenzo Librandi, <a href="/A030621/b030621.txt">Table of n, a(n) for n = 1..5000</a> %t A030621 Accumulate[Which[#==4,1,#==5,-1,True,0]&/@Flatten[IntegerDigits[#,6]&/@ Fibonacci[Range[2,30]]]] (* _Harvey P. Dale_, Jul 21 2014 *) %K A030621 sign,base %O A030621 1,11 %A A030621 _Clark Kimberling_