a(n) = Sum_{k=1..n} binomial(n,k) * sigma_3(k).

Terms

a(0) =1a(1) =11a(2) =58a(3) =243a(4) =866a(5) =2804a(6) =8485a(7) =24387a(8) =67333a(9) =180086a(10) =469338a(11) =1196976a(12) =2996956a(13) =7385837a(14) =17954243a(15) =43125267a(16) =102494548a(17) =241309031a(18) =563341508a(19) =1305142418a(20) =3002938045a(21) =6866090880a(22) =15609292379a(23) =35299794600a(24) =79443050541a(25) =177989130174a(26) =397124963671a(27) =882642816697