Number of fractions in Farey series of order n.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =11a(6) =13a(7) =19a(8) =23a(9) =29a(10) =33a(11) =43a(12) =47a(13) =59a(14) =65a(15) =73a(16) =81a(17) =97a(18) =103a(19) =121a(20) =129a(21) =141a(22) =151a(23) =173a(24) =181a(25) =201a(26) =213a(27) =231a(28) =243a(29) =271