a(n) = Sum_{k=1..n-1} sigma_3(k)*sigma_5(n-k).

Terms

a(0) =0a(1) =1a(2) =42a(3) =569a(4) =4250a(5) =22006a(6) =88004a(7) =293369a(8) =845358a(9) =2186376a(10) =5145646a(11) =11282966a(12) =23143198a(13) =45179324a(14) =83905292a(15) =150271993a(16) =258816840a(17) =433786483a(18) =704268402a(19) =1119633944a(20) =1733618768a(21) =2640037170a(22) =3931060364a(23) =5777392406a(24) =8325691750a(25) =11873200964a(26) =16643954724a(27) =23133008124