Number of fixed polycairos with n cells.

Terms

a(0) =4a(1) =10a(2) =32a(3) =112a(4) =412a(5) =1572a(6) =6148a(7) =24494a(8) =98992a(9) =404650a(10) =1669496a(11) =6941226a(12) =29047568a(13) =122235518a(14) =516860460a(15) =2194691988a(16) =9353657788a(17) =39996019860a(18) =171525222740a(19) =737541708318