Number of triangular regions in the Farey Diagram Farey(n,n), divided by 4.

Terms

a(0) =1a(1) =12a(2) =100a(3) =392a(4) =1554a(5) =3486a(6) =9690a(7) =18942a(8) =38610a(9) =65268a(10) =125116a(11) =186870a(12) =324646a(13) =472546a(14) =713354a(15) =1003888a(16) =1531908a(17) =2000638a(18) =2920970a(19) =3780950a(20) =5102290a(21) =6521198a(22) =8914618a(23) =10889352a(24) =14372890a(25) =17669634a(26) =22409814a(27) =27098466a(28) =34726578a(29) =40504652