a(n) = Sum_{i=0..n} wt(i)^4, where wt() = A000120().

Terms

a(0) =0a(1) =1a(2) =2a(3) =18a(4) =19a(5) =35a(6) =51a(7) =132a(8) =133a(9) =149a(10) =165a(11) =246a(12) =262a(13) =343a(14) =424a(15) =680a(16) =681a(17) =697a(18) =713a(19) =794a(20) =810a(21) =891a(22) =972a(23) =1228a(24) =1244a(25) =1325a(26) =1406a(27) =1662a(28) =1743a(29) =1999