Periodic derivative of n.

Terms

a(0) =0a(1) =0a(2) =3a(3) =0a(4) =5a(5) =6a(6) =3a(7) =0a(8) =9a(9) =10a(10) =15a(11) =12a(12) =5a(13) =6a(14) =3a(15) =0a(16) =17a(17) =18a(18) =23a(19) =20a(20) =29a(21) =30a(22) =27a(23) =24a(24) =9a(25) =10a(26) =15a(27) =12a(28) =5a(29) =6