The number of vertices in a Farey diagram of order (n,n).

Terms

a(0) =5a(1) =37a(2) =313a(3) =1253a(4) =4977a(5) =11253a(6) =31393a(7) =61409a(8) =125525a(9) =212785a(10) =407757a(11) =609361a(12) =1059497a(13) =1541005a(14) =2328621a(15) =3282329a(16) =5006113a(17) =6538721a(18) =9545621a(19) =12352197a(20) =16675101a(21) =21328337a(22) =29149445a(23) =35604513a(24) =47005357a(25) =57782693a(26) =73290609a(27) =88650465a(28) =113587377a(29) =132496021