a(n) = |s(n) - n|, where s = A026255.

Terms

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