a(n) = Sum_{d|n, d <= 3} d^2 + 3*Sum_{d|n, d>3} d.

Terms

a(0) =1a(1) =5a(2) =10a(3) =17a(4) =16a(5) =32a(6) =22a(7) =41a(8) =37a(9) =50a(10) =34a(11) =80a(12) =40a(13) =68a(14) =70a(15) =89a(16) =52a(17) =113a(18) =58a(19) =122a(20) =94a(21) =104a(22) =70a(23) =176a(24) =91a(25) =122a(26) =118a(27) =164a(28) =88a(29) =212