Number of n-edge 3-connected planar maps with a sense-reversing automorphism.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =0a(7) =1a(8) =2a(9) =1a(10) =4a(11) =9a(12) =12a(13) =27a(14) =50a(15) =99a(16) =188a(17) =386a(18) =740a(19) =1528a(20) =3012a(21) =6192a(22) =12376a(23) =25594a(24) =51628a(25) =107135a(26) =218100a(27) =453895a(28) =930812a(29) =1943281