A transform of the large Schroeder numbers.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =13a(5) =27a(6) =69a(7) =161a(8) =415a(9) =1033a(10) =2701a(11) =6983a(12) =18521a(13) =49041a(14) =131723a(15) =354493a(16) =962381a(17) =2620675a(18) =7178285a(19) =19724513a(20) =54430023a(21) =150641937a(22) =418294813a(23) =1164528399a(24) =3250685297a(25) =9094701729a(26) =25501672595a(27) =71649158709a(28) =201687341901