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

Terms

a(0) =8a(1) =92a(2) =816a(3) =3276a(4) =13040a(5) =29452a(6) =82128a(7) =160656a(8) =328212a(9) =556040a(10) =1065660a(11) =1592368a(12) =2768168a(13) =4026972a(14) =6083804a(15) =8572272a(16) =13075848a(17) =17078512a(18) =24932940a(19) =32266036a(20) =43554500a(21) =55698768a(22) =76127780a(23) =92987368a(24) =122756092a(25) =150904228a(26) =191400384a(27) =231497376a(28) =296627368a(29) =346000788