a(0) = 1; for n>0, a(n) = 16 times sum of cubes of divisors of n.

Terms

a(0) =1a(1) =16a(2) =144a(3) =448a(4) =1168a(5) =2016a(6) =4032a(7) =5504a(8) =9360a(9) =12112a(10) =18144a(11) =21312a(12) =32704a(13) =35168a(14) =49536a(15) =56448a(16) =74896a(17) =78624a(18) =109008a(19) =109760a(20) =147168a(21) =154112a(22) =191808a(23) =194688a(24) =262080a(25) =252016a(26) =316512a(27) =327040a(28) =401792a(29) =390240