The number of biconnected squaregraphs with n vertices.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =1a(6) =0a(7) =2a(8) =1a(9) =5a(10) =2a(11) =17a(12) =11a(13) =65a(14) =54a(15) =299a(16) =333a(17) =1508a(18) =2041a(19) =8215a(20) =12971