Red rooted red-black trees with n internal nodes.

Terms

a(0) =1a(1) =0a(2) =1a(3) =4a(4) =6a(5) =4a(6) =2a(7) =8a(8) =32a(9) =96a(10) =256a(11) =608a(12) =1268a(13) =2392a(14) =4177a(15) =6720a(16) =9976a(17) =14064a(18) =19882a(19) =30952a(20) =59080a(21) =138096a(22) =355734a(23) =929040a(24) =2380268a(25) =5940408a(26) =14466720a(27) =34499984a(28) =80786736a(29) =186018208