Number of Q graphs with 2*n vertices symmetrical about a distinguished edge.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =6a(6) =7a(7) =37a(8) =47a(9) =242a(10) =324a(11) =1658a(12) =2300a(13) =11764a(14) =16741a(15) =85741a(16) =124383a(17) =638250a(18) =939880a(19) =4832446a(20) =7202214a(21) =37101556a(22) =55842670a(23) =288180066a(24) =437325262a(25) =2260516372a(26) =3454370352a(27) =17881862308a(28) =27489383818a(29) =142491830992