Total preorders.

Terms

a(0) =5a(1) =24a(2) =79a(3) =223a(4) =579a(5) =1432a(6) =3434a(7) =8071a(8) =18714a(9) =42991a(10) =98127a(11) =222965a(12) =505008a(13) =1141236a(14) =2574845a(15) =5802636a(16) =13065935a(17) =29403439a(18) =66141015a(19) =148734156a(20) =334391354a(21) =751675943a(22) =1689494650a(23) =3797059555a(24) =8533209055a(25) =19176039925a(26) =43091557504a(27) =96831330948a(28) =217586892705