a(n) = n - A326042(n), where A326042(n) = A064989(sigma(A003961(n))).

Terms

a(0) =0a(1) =1a(2) =1a(3) =-7a(4) =4a(5) =4a(6) =5a(7) =5a(8) =-20a(9) =9a(10) =6a(11) =-10a(12) =9a(13) =12a(14) =13a(15) =-33a(16) =14a(17) =-11a(18) =17a(19) =9a(20) =17a(21) =17a(22) =17a(23) =18a(24) =-9a(25) =22a(26) =5a(27) =6a(28) =28a(29) =28