T(n, 2*n-5), T given by A027960.

Terms

a(0) =3a(1) =7a(2) =18a(3) =44a(4) =98a(5) =199a(6) =373a(7) =654a(8) =1085a(9) =1719a(10) =2620a(11) =3864a(12) =5540a(13) =7751a(14) =10615a(15) =14266a(16) =18855a(17) =24551a(18) =31542a(19) =40036a(20) =50262a(21) =62471a(22) =76937a(23) =93958a(24) =113857a(25) =136983a(26) =163712a(27) =194448a(28) =229624a(29) =269703