a(n) = Sum_{k=1..n} k^2*sigma(k), where sigma is A000203.

Terms

a(0) =1a(1) =13a(2) =49a(3) =161a(4) =311a(5) =743a(6) =1135a(7) =2095a(8) =3148a(9) =4948a(10) =6400a(11) =10432a(12) =12798a(13) =17502a(14) =22902a(15) =30838a(16) =36040a(17) =48676a(18) =55896a(19) =72696a(20) =86808a(21) =104232a(22) =116928a(23) =151488a(24) =170863a(25) =199255a(26) =228415a(27) =272319a(28) =297549a(29) =362349