a(n) = Sum_{i=1..m} |d(i) - d(i-1)|, where Sum_{i=0..m} d(i)*2^i is the base-2 representation of n.

Terms

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