a(n) = Sum_{k=1..n-1} k^3*sigma(k)*sigma(n-k).

Terms

a(0) =0a(1) =1a(2) =27a(3) =184a(4) =875a(5) =2700a(6) =7546a(7) =17600a(8) =35721a(9) =72750a(10) =126445a(11) =223776a(12) =353717a(13) =595448a(14) =843750a(15) =1349120a(16) =1827636a(17) =2808837a(18) =3600975a(19) =5306000a(20) =6667920a(21) =9599172a(22) =11509982a(23) =16416000a(24) =19015625a(25) =26605670a(26) =30902310a(27) =41686848a(28) =46948825a(29) =64233000