A031232 - OEIS

%I #6 Apr 26 2019 09:47:42

%S 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,

%T 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,

%U 11,12,13,13,14,15,15,16,15,15,16,15,16,17,16

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

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

%K nonn

%O 1,7

%A _Clark Kimberling_