a(n) = |{m : multiplicative order of 5 mod m=n}|.

Terms

a(0) =3a(1) =5a(2) =3a(3) =12a(4) =9a(5) =37a(6) =3a(7) =28a(8) =18a(9) =47a(10) =3a(11) =180a(12) =3a(13) =53a(14) =81a(15) =176a(16) =9a(17) =446a(18) =21a(19) =564a(20) =39a(21) =117a(22) =9a(23) =884a(24) =180a(25) =53a(26) =360a(27) =244a(28) =21a(29) =5959