a(n) = Sum_{k=1..n} sigma_3(k)^2.

Terms

a(0) =1a(1) =82a(2) =866a(3) =6195a(4) =22071a(5) =85575a(6) =203911a(7) =546136a(8) =1119185a(9) =2405141a(10) =4179365a(11) =8357301a(12) =13188505a(13) =22773721a(14) =35220505a(15) =57132266a(16) =81279662a(17) =127696631a(18) =174756231a(19) =259359435a(20) =352134859a(21) =495847003a(22) =643907227a(23) =912211627a(24) =1160305628a(25) =1551633152a(26) =1969426752a(27) =2600039296