Number of 4-sided regions in the Farey Diagram Farey(n,n), divided by 8.

Terms

a(0) =1a(1) =13a(2) =57a(3) =231a(4) =532a(5) =1497a(6) =2935a(7) =6031a(8) =10273a(9) =19680a(10) =29441a(11) =51261a(12) =74473a(13) =112721a(14) =159299a(15) =242763a(16) =317155a(17) =462930a(18) =598755a(19) =808780a(20) =1035705a(21) =1414983a(22) =1728181a(23) =2282397a(24) =2805375a(25) =3558815a(26) =4306631a(27) =5516710a(28) =6435770a(29) =8126946