Sum_{k>0} (n mod k) * 2^(n-k).

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =6a(5) =23a(6) =16a(7) =89a(8) =106a(9) =267a(10) =364a(11) =1741a(12) =526a(13) =5135a(14) =9360a(15) =17681a(16) =16914a(17) =99347a(18) =71188a(19) =404501a(20) =372758a(21) =892951a(22) =1763352a(23) =7720985a(24) =2809882a(25) =17154075a(26) =34201628a(27) =82821149a(28) =83623966a(29) =435683359