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 A030566 #8 Feb 26 2025 16:58:41
%S A030566 0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,
%T A030566 0,0,0,0,1,1,0,1,1,2,2,3,3,4,4,5,6,7,6,5,5,4,4,3,3,2,2,1,2,1,0,0,0,0,
%U A030566 0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0
%N A030566 a(n)=(# 4's)-(# 5's) in first n terms of A030548.
%C A030566 There is no negative term in the first million terms of this sequence. - _Harvey P. Dale_, Feb 26 2025
%t A030566 Accumulate[Which[#==4,1,#==5,-1,True,0]&/@Flatten[Table[IntegerDigits[n,6],{n,50}]]] (* _Harvey P. Dale_, Feb 26 2025 *)
%K A030566 nonn
%O A030566 1,44
%A A030566 _Clark Kimberling_