(# 1's)-(# 2's) in first n terms of A030604.

Terms

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