a(n)=(# 1's)-(# 2's) in first n terms of A031253.

Terms

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