a(n) = Sum_{d|n} d*tau(d)^2.

Terms

a(0) =1a(1) =9a(2) =13a(3) =45a(4) =21a(5) =117a(6) =29a(7) =173a(8) =94a(9) =189a(10) =45a(11) =585a(12) =53a(13) =261a(14) =273a(15) =573a(16) =69a(17) =846a(18) =77a(19) =945a(20) =377a(21) =405a(22) =93a(23) =2249a(24) =246a(25) =477a(26) =526a(27) =1305a(28) =117a(29) =2457