Ratio A095110(n)/A000079(n-2) rounded down.

Terms

a(0) =2a(1) =6a(2) =12a(3) =20a(4) =37a(5) =52a(6) =106a(7) =200a(8) =369a(9) =657a(10) =1226a(11) =2191a(12) =4268a(13) =8076a(14) =15291a(15) =28931a(16) =55124a(17) =105982a(18) =202482a(19) =391505