a(n) = Sum_{d|n} rad(d)^(n/d), where rad(d) = A007947(d) is the squarefree kernel of d.

Terms

a(0) =1a(1) =3a(2) =4a(3) =7a(4) =6a(5) =24a(6) =8a(7) =23a(8) =31a(9) =68a(10) =12a(11) =196a(12) =14a(13) =192a(14) =384a(15) =279a(16) =18a(17) =1473a(18) =20a(19) =1792a(20) =2552a(21) =2192a(22) =24a(23) =12068a(24) =3131a(25) =8388a(26) =19714a(27) =19124a(28) =30a(29) =116474