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 A031265 #6 Jan 14 2024 17:09:45
%S A031265 1,1,2,1,2,2,3,3,3,4,4,4,4,3,3,3,3,3,3,4,4,4,5,4,3,4,3,3,4,3,3,4,5,6,
%T A031265 7,8,8,9,9,8,9,9,9,10,10,10,11,11,12,13,13,13,14,14,13,14,14,14,15,15,
%U A031265 15,15,14,15,15,14,14,14,15,14,14,15,15,15,16
%N A031265 a(n)=(# 1's)-(# 0's) in first n terms of A031253.
%t A031265 Accumulate[Flatten[Table[IntegerDigits[2n-1,5]/.{0->-1,2->0,3->0,4->0},{n,60}]]] (* _Harvey P. Dale_, Jan 14 2024 *)
%K A031265 nonn
%O A031265 1,3
%A A031265 _Clark Kimberling_