A031266 a(n)=(# 1's)-(# 2's) in first n terms of A031253.

1, 1, 2, 2, 3, 2, 3, 3, 2, 3, 2, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 3, 4, 4, 4, 5, 6, 7, 8, 9, 9, 10, 9, 9, 10, 9, 8, 9, 8, 8, 9, 9, 10, 11, 11, 11, 12, 12, 12, 13, 13, 12, 13, 13, 13, 12, 12, 13, 12, 12, 12, 11, 12, 12, 11, 12, 11, 10, 11, 11

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Programs

Mathematica

Accumulate[Which[#==1,1,#==2,-1,True,0]&/@(Table[IntegerDigits[2n-1,5],{n,60}]//Flatten)] (* Harvey P. Dale, Apr 16 2024 *)