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 A030349 #6 Jul 25 2024 12:18:12
%S A030349 1,1,0,1,2,3,3,4,3,3,4,4,4,4,3,2,3,4,3,4,4,3,4,3,4,5,6,7,8,8,9,10,9,9,
%T A030349 10,11,11,12,12,12,13,12,11,11,12,11,11,11,10,10,9,10,10,11,12,12,12,
%U A030349 13,13,12,12,12,13,13,13,13,13,13,12,11,10,11
%N A030349 (# 1's)-(# 0's) in first n terms of A030341.
%t A030349 Accumulate[Which[#==1,1,#==0,-1,True,0]&/@Flatten[Table[Reverse[IntegerDigits[n,3]],{n,40}]]] (* _Harvey P. Dale_, Jul 25 2024 *)
%K A030349 nonn
%O A030349 1,5
%A A030349 _Clark Kimberling_