a(n) = number of conjugacy classes in PSL_4(prime(n)).

Terms

a(0) =14a(1) =29a(2) =49a(3) =217a(4) =757a(5) =613a(6) =1327a(7) =3661a(8) =6409a(9) =6349a(10) =15457a(11) =13057a(12) =17707a(13) =40789a(14) =53137a(15) =37993a(16) =104581a(17) =57757a(18) =152797