a(n) = Sum_{k<=n} A007955(k), where A007955(m) = product of divisors of m.

Terms

a(0) =1a(1) =3a(2) =6a(3) =14a(4) =19a(5) =55a(6) =62a(7) =126a(8) =153a(9) =253a(10) =264a(11) =1992a(12) =2005a(13) =2201a(14) =2426a(15) =3450a(16) =3467a(17) =9299a(18) =9318a(19) =17318a(20) =17759a(21) =18243a(22) =18266a(23) =350042a(24) =350167a(25) =350843a(26) =351572a(27) =373524a(28) =373553a(29) =1183553