A031232 a(n)=(# 1's)-(# 2's) in first n terms of A031219.

1, 0, 0, 0, 1, 1, 2, 3, 4, 3, 4, 4, 5, 5, 4, 4, 3, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 3, 4, 4, 3, 4, 4, 4, 5, 5, 5, 6, 7, 7, 8, 9, 10, 11, 12, 11, 12, 13, 13, 14, 15, 15, 16, 15, 15, 16, 15, 16, 17, 16

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Programs

Mathematica

Accumulate[Which[#==1,1,#==2,-1,True,0]&/@Flatten@IntegerDigits[ Range@ 40,5]] (* Harvey P. Dale, Apr 26 2019 *)