a(n) = 2*sigma(n^2) - sigma(n)^2.

Terms

a(0) =1a(1) =5a(2) =10a(3) =13a(4) =26a(5) =38a(6) =50a(7) =29a(8) =73a(9) =110a(10) =122a(11) =22a(12) =170a(13) =222a(14) =230a(15) =61a(16) =290a(17) =173a(18) =362a(19) =158a(20) =458a(21) =566a(22) =530a(23) =-298a(24) =601a(25) =798a(26) =586a(27) =398a(28) =842a(29) =458