Total sum of the number of divisors of the element sum over all nonempty subsets of [n].

Terms

a(0) =1a(1) =5a(2) =16a(3) =40a(4) =96a(5) =217a(6) =469a(7) =1011a(8) =2147a(9) =4497a(10) =9389a(11) =19489a(12) =40256a(13) =82948a(14) =170413a(15) =349158a(16) =714153a(17) =1458199a(18) =2972683a(19) =6052561a(20) =12308971a(21) =25006177a(22) =50755272a(23) =102933086a(24) =208594116a(25) =422432018a(26) =854956112a(27) =1729360940a(28) =3496259940a(29) =7065053883