a(n) = Sum_{d divides n} d*2^(n-n/d).

Terms

a(0) =1a(1) =5a(2) =13a(3) =41a(4) =81a(5) =257a(6) =449a(7) =1313a(8) =2497a(9) =6465a(10) =11265a(11) =33665a(12) =53249a(13) =143617a(14) =269313a(15) =672257a(16) =1114113a(17) =3159041a(18) =4980737a(19) =13568001a(20) =23904257a(21) =57675777a(22) =96468993a(23) =275980289a(24) =424673281a(25) =1090535425a(26) =1963720705a(27) =4823482369a(28) =7784628225