(# 1's)-(# 0's) in first n terms of A003137.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =2a(5) =3a(6) =4a(7) =4a(8) =4a(9) =3a(10) =3a(11) =4a(12) =4a(13) =4a(14) =5a(15) =4a(16) =3a(17) =4a(18) =3a(19) =4a(20) =5a(21) =4a(22) =4a(23) =5a(24) =6a(25) =5a(26) =6a(27) =7a(28) =8a(29) =9