A031231 (# 1's)-(# 0's) in first n terms of A031219.
1, 1, 1, 1, 2, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 6, 5, 6, 5, 6, 7, 6, 6, 7, 6, 6, 7, 6, 6, 7, 8, 7, 8, 9, 10, 11, 12, 12, 13, 14, 14, 15, 16, 16, 17, 17, 16, 17, 17, 18, 19, 19
Offset: 1