a(0)=0; for n>0, a(n) = Sum_{d|n} d*2^(n/d).

Terms

a(0) =0a(1) =2a(2) =8a(3) =14a(4) =32a(5) =42a(6) =104a(7) =142a(8) =320a(9) =554a(10) =1128a(11) =2070a(12) =4352a(13) =8218a(14) =16696a(15) =32934a(16) =66176a(17) =131106a(18) =263480a(19) =524326a(20) =1050912a(21) =2097634a(22) =4198488a(23) =8388654a(24) =16786688a(25) =33554642a(26) =67125352a(27) =134219390a(28) =268468960a(29) =536870970